CLEVELAND -- Pete Alonso had a pretty good night. A fun evening in the middle of what he called a fantasy season so far. After all, the rookie first baseman for the New York Mets hit three walk-off homers to win the 2019 Home Run Derby.

In the first round, matched up against hometown hero Carlos Santana of the Indians, Alonso hit his 14th home run with one second left on the clock, eliminating Santana, earning a chest-bump from his cousin Derek Morgan, his pitcher for the evening, and receiving a chorus of boos from Cleveland fans who were disappointed in Santana's early exit.

"I didn't think I'd ever be booed at a Home Run Derby, to be honest with you," Alonso said. "But I guess that's the hometown home cooking. Dealt with some adversity but we overcame, and pretty much just survive and advance. That was it."

Alonso's task in the second round was a little more difficult. His opponent, Atlanta Braves sophomore sensation Ronald Acuna Jr., blasted 19 home runs, a total that would have won all but one matchup in last season's Home Run Derby. More than halfway through the four-minute round, Alonso had just seven home runs. He called a timeout at the 1:49 mark. Then he heated up. With 30 seconds remaining, Alonso was up to 15 home runs. And as the clock dwindled down to zero, he homered on his final two swings, with No. 20 a towering 453-foot blast that landed in the trees beyond the center-field fence.

Alonso celebrated with what could be best described as a double-shoulder downward fist-bump and a couple of "Yeah!" shouts that might have been heard all the way back in Queens. He was into the finals, facing Vladimir Guerrero Jr., who had prevailed over Joc Pederson in the most epic single-round showdown in Home Run Derby history, a battle that required three tie-breaker rounds before Guerrero held on to win 40 to 39 when Pederson hit a ground ball on his final swing.

Yes, everyone will remember the Guerrero-Pederson matchup for the ages. But like Justin Morneau in 2008, when he beat Josh Hamilton after Hamilton's then-record 28-homer round at Yankee Stadium, it was Alonso who walked away with the double-bat silver trophy -- and the new $1 million award for the champion.

It took Alonso's third walk-off home run of the competition to do it, after Guerrero had slammed an impressive 22 home runs. Alonso started the final round off better than his first two rounds, with seven home runs at the 2:47 mark, when he used his first timeout. (Players get two in the final round.) Morgan would say that they found their groove as the contest went on. He had practiced three times recently with Alonso, the latest last week during the Subway Series at Citi Field.

That session earned Morgan final approval from Alonso's Mets teammates.

"We put on a show for early work. And he really got the stamp of approval, because you've got veterans like Robbie Cano, Todd Frazier and Wilson Ramos making sure he's throwing money BP, and he was putting it right there for me," Alonso said. "He impressed a lot of the guys, and especially all the coaching staff too. They were really impressed and everyone thought, 'Look, y'all are going to win this thing,' and they're right."

At the timeout, All-Star teammate Jeff McNeil -- Alonso's designated water man during timeouts -- gave the big slugger a little advice.

"I told him that he didn't need to try to pull the ball. Just stay middle," McNeil said. "We kind of talked about that before the semifinal round. Those balls are going out. He got a little pull-happy maybe, so stay up the middle of the field and hit some bombs."

Indeed, the ability to spray home runs -- and drive the ball to center field -- is Alonso's strength during real games, and it proved beneficial during the Derby, as well:

Here's @mets Pete Alonso's final home run spray chart. Absolutely beautiful ??? pic.twitter.com/qpkAB00Rq8

— Daren Willman (@darenw) July 9, 2019

With 1:30 left in the final round, he was up to 14 home runs. His 16th homer was a low screamer that just cleared the fence in left field. He used his second timeout with 1:02 remaining, sitting on 18 home runs. While Guerrero had burned up a month's worth of calories in twice breaking Hamilton's record, Alonso was more rested. He admitted this played to his advantage.

"I'm just happy that I didn't need the extra time [in the earlier rounds], because that's extra swings," Alonso said. "That could have possibly carried over into the next round. So I'm happy that I was able to conserve as much energy throughout the event, and that was huge. Without being where I was in the seeding, I put myself in a good position with the regular season. Without that, it may have been a different story. I'm really fortunate with how the brackets worked out. But survive and advance."

Because he was the higher seed and hit after Guerrero in the finals, Alonso knew the number he had to beat. He had a minute left -- plus the bonus time earned for hitting two 440-foot home runs -- to hit five home runs. No. 19 was a low liner to straightaway center, but Alonso is so strong it kept carrying, just inching over the wall by a few feet.

Then came walk-off No. 3. With 18 seconds left, Alonso hit a patented high-arcing fly ball into left-center, four or five rows, a shot measured at 429 feet. Not his longest blast of the night -- that one went 467 feet -- but it made him the 2019 Home Run Derby champion. He raised his arms in triumph, and Morgan leapt into his arms:

TAKE. IT. HOME. #HomeRunDerby ? pic.twitter.com/Sr5WenLWG7

— New York Mets (@Mets) July 9, 2019

Alonso received hugs from McNeil and Guerrero. He said he would donate 5% of his winner's check to the Wounded Warrior Project -- both his grandfathers served in the military -- and 5% to Tunnel to Towers, a foundation that benefits first responders. Maybe he'll give a little tip to his cousin. The musician Daddy Yankee gave Alonso a big silver medallion that he wore around his neck.

"It's sweet. It even spins," Alonso said. "This is cool. I think I might play the game tomorrow with this on."