The NBA Finals will not end in a sweep as Luka Dončić and the Dallas Mavericks put on a show in a dominating Game 4 win against the Boston Celtics.

The emphatic 122-84 win at American Airlines Center gave the Mavs their first win of the series, with Dončić putting up 29 points, 5 rebounds and 5 assists and Kyrie Irving contributing 21 points and 6 assists. Celtics duo Jayson Tatum and Jaylen Brown were held to 15 and 10 points, respectively, their lowest totals of the series.

The Celtics still have a 3-1 advantage as they head home for Game 5 at TD Garden, where they will aim to close the series and win their 18th NBA championship. Dallas took the first step in what will be a steep, uphill battle against the Celtics -- no NBA team has overcome a three-game deficit to win a playoff series.

How did the Mavericks bounce back to get their first win of the series? What went amiss for the Celtics, and what do they need to get back on course? Our NBA insiders break down Dallas' dominating performance and what to expect for Monday's Game 5 (8:30 p.m. ET, ABC).

What did Dallas finally do right in Game 4?

Tim MacMahon: Dončić was locked in, and the Mavs followed his lead. Dončić heard the criticism following Game 3 and responded the right way. He avoided the distraction of complaining to officials, instead pouring that energy into defensive effort and interacting with his teammates. He efficiently attacked offensively, too, scoring 22 of his 29 points in the paint. Dončić's focused, fighting spirit was infectious. The Mavs, especially rookie big man Dereck Lively II, followed suit and physically dominated the Celtics.

Chris Herring: Everyone, Dončić included, finally embraced the challenge of sitting down and defending the Celtics when they put the ball on the floor. Irving battled with Tatum, forcing the All-NBA wing into a charge call. The Mavs swarmed during a separate Boston possession and the Celtics got whistled for a shot-clock violation. Most notably, perhaps, was the fact that Dončić competed on defense, forcing misses on the Celtics' first six attempts with him serving as the primary defender. (He forced Jrue Holiday -- someone who hadn't committed a single turnover all series -- into four turnovers when serving as Holiday's primary defender.) Those elements helped Dallas hold the Celtics to just 35 points in the first half -- their lowest-scoring half under head coach Joe Mazzulla.

Ramona Shelburne: I knew something was different when Lively hit a 3-pointer (his first on just his third attempt all season) in the first quarter. There are all sorts of reasons Dallas lost the first three games of this series, but one of the biggest was just simple math. Boston was relentless in its 3-point assault, and the Mavericks were just swimming against a riptide the whole time. You just can't keep up when a team is taking 56% of its shots from behind the 3-point arc and making them at a decent clip.

Before Friday, Boston's plus-49 differential in 3-point attempts was the largest through three games in NBA history. In Game 4, the Mavs fared better with 37 attempts compared to 41 by the Celtics. That opened up the rest of the floor for the Mavericks, who have an advantage in the paint with Lively and Daniel Gafford, and finally evened up the math, which had been stacked against them all series.

What kept the Celtics from finishing this in a sweep?

Herring: As much as Dallas did its part in defending with more force, the Celtics also shot far worse on open looks to start the game than they did in the first three games of the series. Boston shot better than 50% on open looks in each of the previous three first halves. But the Celtics shot only 3-of-9 on their open tries going into halftime of Game 4, by which point they were already down by 26.

That covers part of what was wrong on offense for Boston. But the defense? Uncharacteristically, the Celtics' effort was beyond shaky, particularly once the Mavs began pouring it on in the third period. It wasn't a title-clinching sort of effort, to say the least.

Shelburne: Dončić and Irving finally played the kind of games that had propelled the Mavericks through the Western Conference playoffs, finishing with a combined 50 points, 9 rebounds and 11 assists. They each deserve a ton of credit, especially because of the criticism they've faced following the first three losses.

The biggest difference in this game, though, was Dallas' reserves. Lively's valiant effort gave the Mavs an inside presence and finally helped take advantage of Boston's lack of rim protection, with Kristaps Porzingis absent for the second straight game due to his left leg injury. Dallas had gotten very little from any of its reserves throughout the series, leading coach Jason Kidd to play 11 guys in Game 3 -- searching in vain for some kind of production. Lively gave it to Dallas with scoring and rebounding that set the tone for the entire game.

MacMahon: Give the Mavs credit, but this was a dud by a Boston squad that seemed to think it was set for the duck boats and the championship parade. The Mavs scored 22 points in the paint in the first quarter, an embarrassing total for the Celtics to concede. It probably would have helped if Porziņģis and his rim protection were available, but Dallas was determined to be the aggressor, and Boston didn't respond to getting punched in the mouth. Mazzulla waved the white flag by pulling his starters with 3:18 remaining in the third quarter.

Back to Boston. This series ends in Game 5 if ___ .

Shelburne: The Celtics shoot better than 36% from the field. That sounds really simple, but it kind of is when you take as many 3-pointers as the Celtics do. Boston lives by the 3 and dies by it too, sometimes. When the Celtics are making 3s, they have space to drive and post up. When they're not, that space closes up and it gets harder to get into the offensive system that ranked as the best in NBA history. Porzingis was supposed to be the antidote to games in which Boston didn't shoot well. His unique skill set creates matchup advantages every time he's on the court. After he missed another game because of injury, it remains to be seen what his availability will be for the rest of the series.

MacMahon: The Celtics show up and the Garden ghosts keep haunting Irving. He finally beat his former team for the first time since stepping on that cartoon leprechaun logo's eye, but he still hasn't won in Boston since that 2021 playoff series when he was with the Brooklyn Nets. The Mavs will need the version of Irving they got in the past two games -- and most of the time all season -- to pull off a road upset and bring the series back to Dallas.

Herring: The Celtics take a deep breath and regroup, then force Dallas to rotate by moving the ball better. Yes, the Mavericks played with much greater effort defensively. But it's worth remembering that Boston was getting whatever it wanted when it drove to the basket the first three games. The Mavs tightened up in Game 4, and it seemed to catch the Celtics off guard. Boston's style of play and willingness to consistently compete on both sides of the floor should eventually win out, and it wouldn't be surprising if that happened in Game 5.