CHICAGO -- THE BULLS were staring at what seemed like an unavoidable 0-2 start.

The scoreboard showed the Toronto Raptors with a 91-88 lead and a mere 19.1 seconds left on the clock. Toronto had the ball preparing to inbound, and the Bulls would likely be forced to foul, sending the Raptors to the line to ice the game.

That's when Alex Caruso took over.

Toronto forward Pascal Siakam was the inbounder and saw Scottie Barnes break off a screen and head toward center court. Making a beeline behind Barnes was Caruso, who leaped into the air to contest the pass. Barnes secured the ball briefly, but it came loose and Caruso dove on the floor to secure possession for Chicago. He got the ball to DeMar DeRozan, who made a layup and was fouled, sending him to the line for a potential game-tying free throw.

DeRozan missed from the line, but Caruso was there to save the day again. He batted an offensive rebound into the hands of DeRozan for another layup attempt. This time, DeRozan couldn't convert.

It seemed as if Chicago had wasted its best chance, but Caruso still had some magic left. With Chicago trailing by one with 3.5 seconds remaining, he drew an offensive foul from Siakam on an inbounds play, giving the Bulls the ball back again.

When the game was pushed into overtime, Caruso had one last game-saving play. Toronto was leading by two with 10 seconds remaining when Caruso stripped the ball from Barnes, who was heading toward the basket for a layup, got it into the hands of a teammate and then ran the length of the floor into an open corner. That's where Zach LaVine spotted him and passed him the ball for a go-ahead 3-pointer, leading the Bulls -- who trailed by 17 with under five minutes to go -- to one of the most unlikely wins of this young season.

"Some of the things he does, diving on the boards, sacrificing his body, you've got to follow behind your brother when you see that," DeRozan told ESPN. "And you want to help him as much as possible."

The Bulls built their roster around DeRozan, LaVine and Nikola Vucevic -- three All-Stars who have made careers out of their skills on offense -- but it has been Chicago's defense that has been the more successful unit.

Led by Caruso, the Bulls finished fifth in the NBA in defensive efficiency during the 2022-23 season (Chicago's offense ranked 24th). With Caruso on the floor last season, the Bulls' defense yielded an average of 106.5 points per 100 possessions, a number that rose to 112.5 with him off it. Individually, Caruso ranked among the top five in field goal percentage allowed as the contesting defender last season, led all guards in defensive LEBRON -- a catch-all metric that measures defensive impact -- ranked in the top five in steals per 36 minutes and led the NBA in deflections per 36 minutes among players to play at least 1,000 minutes, per NBA Advanced Stats.

"He helps the entire team, lifts the energy and he pretty much quarterbacks the defense when he's out there," LaVine told ESPN.

Just how good is Caruso, who was a first-team All-Defensive selection despite starting just 36 of his 67 games last season and has come off the bench for every Bulls game so far this season? DeRozan said he could see Caruso winning Defensive Player of the Year.

"He's our Ray Lewis. He's the Deion Sanders. He's the Charles Woodson," DeRozan told ESPN. "He definitely is one of those great, vocalist, communicators and competitors when it comes to that end of the ball.

"He's a guy that without a doubt can win it for sure."

CARUSO APPRECIATES THE praise, but he is not ready to call himself a future Defensive Player of the Year just yet. But given how far he has already come in his seven NBA seasons, he's not going to discount the possibility.

"I'm sure there's a lot of people who didn't think I'd be in the NBA, who didn't think I'd be on a championship team, didn't think I'd be first-team all-defense," Caruso told ESPN. "And there's probably a bunch of people that don't think I can win a Defensive Player of the Year. I don't ever rule anything out just because I continue to impress myself with the heights I can reach.

"I don't know if necessarily I'm going to go out and make that my sole focus. I'm going to concentrate on doing my job and helping the team win, that's when my success comes with it. But you never rule it out."

Caruso went undrafted in 2016 out of Texas A&M, where he's the school's all-time leader in steals, and played just 16 minutes per game in three summer league games for the Philadelphia 76ers before landing with the Oklahoma City Blue, the G League affiliate of the Oklahoma City Thunder.

Caruso's first break in the NBA came the following offseason when he was invited to summer league with the Los Angeles Lakers. He filled in one game as a starter for an injured Lonzo Ball and after a productive showing earned his way into the rotation, helping guide the Lakers to the summer league championship and eventually earning a two-way deal with the NBA team.

"I had to work and earn everything that I got," Caruso said.

After two seasons splitting his time between Los Angeles and the Lakers' G League affiliate, the South Bay Lakers, Caruso landed a two-year, $5.5 million contract in summer 2019. When the Lakers won the 2020 NBA championship in the Orlando, Florida, bubble, Caruso was a key reserve, coming in sixth on the team in playoff minutes.

"Every time that I've moved on to a new team or to a new setting in my career, I've been ready for the challenge and opportunity to grow and push myself to maybe somewhere I didn't think I could get to or I didn't have on my list," Caruso said. "But I see that it's attainable and something I can chase. For me, I can't overstate how proud of myself I am, but still very hungry and ready for more challenges."

With the Lakers, Caruso got to learn firsthand watching LeBron James and a late-career Rajon Rondo, two players he credits for the way he plays defense. Caruso saw the preparation both players put into studying their opponents that allowed them to anticipate other teams' action. And they were both constant communicators on the court, making sure their teammates were always in the best positions.

Those are principles Caruso carried with him when he signed a four-year, $37 million contract with Chicago in summer 2021. He knew he was stepping into a larger role with the Bulls and could assert himself in the way he had seen James and Rondo do so on the Lakers.

"Those guys are just incredible at it," Caruso said. "They're masters of it. It's somewhere I'm trying to get to. But seeing them do it, taking that into a new opportunity, new role, bigger role, where I'm the loudest voice most of the time, just trying to put guys in position for successful possessions.

"A lot of times if you can talk to them beforehand, they don't have to go through and think during the play, they can just react and play to their abilities. It's a win for us."

THE BULLS ARE in Year 3 with Caruso and their core of three All-Stars, but they've yet to have any kind of sustained success. Caruso missed half of the 2021-22 season -- which ended in a first-round playoff exit -- because of multiple injuries. Last season, Chicago failed to make the playoffs, losing in the play-in tournament to the Miami Heat, who went on to reach the NBA Finals.

Already this season the Bulls have held an unprecedented players-only meeting after the first game of the year against the Thunder, picked up a wild victory against the Raptors, lost to the Detroit Pistons despite receiving 51 points from LaVine and then pulled off another comeback win against the Indiana Pacers when benches cleared in the process.

Last season, no trio in the NBA played more minutes together than DeRozan, Vucevic and LaVine, yet Chicago was outscored by 13 points with those three players on the floor. This season, in 150 minutes together, the trio has been outscored by 63. Bulls coach Billy Donovan does have an available solution to get better results from his stars: pairing them with Caruso.

Last season, the Bulls outscored their opponents by 128 points when LaVine, DeRozan and Vucevic shared the floor with Caruso. That was Chicago's best four-man lineup. However, somewhat perplexingly, they have barely shared the floor this season, playing only 67 total minutes together (none during the first game of the season), outscoring their opponents by 10 points in those minutes. In fact, of the 10 Chicago four-man lineups to play at least 50 minutes together and post a positive plus-minus this season, nine of them involve Caruso.

However, the Bulls used Patrick Williams, the No. 4 overall pick from the 2020 NBA draft, in the starting lineup to start the season, despite continued lackluster results. When Williams shared the floor with DeRozan, LaVine and Vucevic last season, the Bulls were outscored by 55 points. That was one of six four-man lineups across the entire NBA to play 1,000 minutes together and the only one that failed to finish with a positive plus-minus.

Donovan initially resisted calls for a lineup change, saying before the Bulls' loss to the Pistons on Oct. 28, "I wouldn't [make a lineup change] from the standpoint of, 'Oh, I'm just taking him out of the starting lineup because he's got to do this, this and this, and he's not doing it.' I think it would be more of, 'What's the best thing for our team?' And then making the decision based on that.''

Over the next three games, Williams went scoreless twice (both Bulls losses) and was eventually replaced in the starting lineup, but not by Caruso. Instead, Torrey Craig took the starting assignment. In the 63 minutes Craig has played alongside the DeRozan-LaVine-Vucevic trio this season, the Bulls have been outscored by 69 points.

The Bulls have remained reluctant to start Caruso, as Donovan has cited Caruso's health as a concerning factor. The Bulls believe they can better control Caruso's minutes as a reserve. But when the Bulls were desperately trying to make the play-in tournament at the end of last season, they inserted Caruso into the starting lineup just before the All-Star break and watched the team go 13-6 during those starts.

"The most important thing with Alex is availability," Donovan said Monday night when asked why Caruso isn't in the starting lineup. "He helps our team when he's out there. When he starts getting consistently close to 30 minutes per night, that's when he has difficulty -- when things have flared up for him and now he's out for a period of time. So, the starting part, yeah, I've thought about that, looked at it, but it's really hard with his minutes sometimes."

Caruso is a regular for the Bulls in the fourth quarter and a mainstay in their closing lineups at the end of games. He almost willed the Bulls to another win Wednesday night against the Phoenix Suns when he shot 7-of-9 for 19 points and guarded Suns superstar Kevin Durant in the fourth quarter and overtime. The Bulls were plus-24 with Caruso on the floor on Wednesday, but dropped the game in overtime, 116-115, to fall to 3-6 on the season.

Caruso (6-foot-4) matched up with Durant (6-foot-10) in 14 half-court matchups according to Second Spectrum, 13 of which came in the fourth quarter or overtime. Durant did not score any points in those matchups, including a potential game-winning jumper at the buzzer in regulation.

Great defense by AC to force OT @ACFresh21 | #SeeRed pic.twitter.com/6QjCa26GYi

Chicago Bulls (@chicagobulls) November 9, 2023

"First of all, it's just his mentality," Durant said. "A hard worker that's going to do all that he can for his teammates. Great teammate that plays hard and that makes up for a lot of mistakes.

"He's a phenomenal player, phenomenal -- I don't even want to call him a role player. He's just a guy that you can plug with any lineup and he's going to make the right reads, the right plays on the defensive and offensive side. Bulls are lucky to have him."

But in order for Caruso to contend for a future Defensive Player of the Year award, LaVine believes the Bulls need to start getting more wins, which will bring even more recognition.

"He's good enough," LaVine said. "And if we're in a position where we're winning and it's recognized, that's all it is. I think he was the best defensive guard last year, and I think some of his numbers showed it."

For now, Caruso's focus remains not on winning a future award, but trying to help the team win games. As the Toronto game showed, he'll do whatever it takes to aid that goal, and then keep doing it again until the final buzzer sounds.

"Obviously I had a really good year individually defensively, but as a team to be top five in defense with what people will classify some of our guys as non-defenders, it's a really big achievement," Caruso said. "Now I think the step for us is to take that and turn that into wins. Not just having a top-five defense but getting the offense to match it and winning ballgames."