When the Mets needed a swing Sunday night against the Padres, when they needed one more big fly from Pete Alonso, that is exactly what he gave them. He knocked one ball out of Citi Field and nearly knocked another out, and once again, he looked as valuable as any slugger in baseball, including the guy across town who wears No. 99 for the Yankees.

“Alonso is a beast,” ESPN’s David Cone, who played ball once on both sides of New York City, told me after the Mets' 8-5 win over the Padres.

Atlanta had lost earlier in the day, something the Braves hardly ever do, against the Angels. But if the Mets lost to the Padres, which meant getting swept at home by San Diego, what had been a 10 1/2-game lead over the Braves on June 1 would have remained a half-game.

Now, after being shut down by Padres pitching on both Friday night and Saturday night and leaving what felt like a subway car worth of runners on base, they hadn’t gotten their first hit off Joe Musgrove until the fifth inning and they were losing, 1-0, to the Padres when Alonso came to the plate with Starling Marte on third and Francisco Lindor on second in the bottom of the sixth.

At this point, the Mets had scored four runs in their past three games, going back to their game against the Cubs at Wrigley Field before the All-Star break. The Mets and their fans needed something to happen before the Padres left town, and now.

The Polar Bear, Alonso, happened. The beast that Cone talked about was the bear. Alonso launched one 425 feet, burying his 25th homer deep into the left-field seats and deep into the night. The Mets had life and so did the ballpark. Before the inning was over, they had scored five runs and sent nine guys to the plate, and then when Alonso came up again the next inning, he hit one over the glove of Esteury Ruiz and off the top of the right-field wall and knocked in his 82nd run of the season (Judge has 81), on the night when he reclaimed the RBI lead for the whole sport.

The Mets have made some big comebacks this season in the late innings. In late April, they were down, 2-0, in St. Louis and down to their last strike against the Cardinals when they scored five runs after that. In May, they from even further back against the Phillies on the road, also in the ninth, turning a 7-1 deficit into a rousing 8-7 victory. But somehow just coming from 1-0 down against the Padres on Sunday Night Baseball felt like as important a comeback as they’ve had all season under Buck Showalter.

“You just can’t get swept,” Alonso said when it was over.

He did not say “you don’t want to be swept.” He said you can’t be. And then he wouldn’t let the Mets get swept. He had help, of course. There were terrific, grinding at-bats from Lindor and Mark Canha as the Mets finally found their offense. Daniel Vogelbach, the new guy who is built like a beer keg, got his first Mets hit and showed off surprising speed for a big man as he scored a run. Edwin Díaz continued a truly dazzling season when he came in to clean up an inherited mess in the ninth. The Mets got to 59-37 the hard way. But got there. They moved a game and a half in front of the Braves, in what is going to be baseball’s great race the rest of the way.

The Braves don’t go away. Neither so the Mets while they wait for Jacob deGrom to finally make his first start of the season. Lindor, having a better season than you think, has 16 homers and 66 RBIs. Max Scherzer, at 37, has mostly pitched like he’s still 27. Díaz has been blowing away the world.

But it is Alonso, the kid from Tampa, Fla., who has provided the same kind of danger in the middle of the Mets lineup that Mike Piazza once did. It is Alonso who is the team’s beating heart. He didn’t win the Home Run Derby for the third time in Los Angeles, knocked out by the kid from Seattle, Julio Rodríguez. But it turns out he saved a little something to bring back home with him. He hit one out Sunday night -- nearly made it two.

It is always worth mentioning that he does this in a season that really began for him four months ago when he was on his way from Tampa to Port St. Lucie, Fla., to begin Spring Training, with an accident that had his truck flipping over in the air while his wife watched, an accident that could have killed him.

“I'm still dealing with some pretty bad PTSD from it, to be completely honest with you,” he wrote recently, and honestly, in The Players Tribune.

“He is a sweet soul,” Showalter said, “with a good heart.”

The Mets needed a big swing on Sunday. You know who gave it to them. A bear with the heart of a lion.