Even their fans got in on the robbery.
Alonso hit a tying home run off imploding Yankees closer Aroldis Chapman leading off the last inning, Jose Peraza lined a go-ahead two-run double that was aided by interference from a visiting fan in the Bronx and the Mets stunned their crosstown rivals 10-5 Sunday to open a split doubleheader.
''It was fun,'' Alonso said between games. ''Let's do it again, I don't know, maybe like an hour from now.''
After roughing up Yankees ace Gerrit Cole in a back-and-forth game, Alonso opened the seventh by dropping his barrel on Chapman's 1-2 slider near the bottom of the zone and lofting it into the visitor's bullpen to tie it at 5.
Chapman then plunked Michael Conforto, walked Jeff McNeil and was promptly yanked by manager Aaron Boone.
Pinch-hitter Kevin Pillar singled to load the bases, Lucas Luetge struck out pinch-hitter James McCann, and Peraza ripped a ball that would've hit midway up the left-field wall. Yankees outfielder Tim Locastro might have had a play on it, but a fan in a Mets jersey reached over to catch the ball with his glove.
Confused players and fans initially had no idea where the ball went. Locastro pointed at the fan angrily, and umpires conferred on the infield before awarding Peraza two bases. The Yankees didn't argue.
''At no point did I realize a fan had caught the ball,'' Peraza said via translator.
Brandon Nimmo followed with a two-run single and Francisco Lindor added an RBI hit before Alonso struck out to end the inning. The NL East-leading Mets also batted around during an inning in an 8-3 win Saturday at Yankee Stadium.
The clubs were set to conclude the season's first Subway Series with a 7 p.m., seven-inning nightcap. A season-high 42,714 tickets were sold for the opener, topping Saturday's total of 40,047 for the largest crowd at either New York stadium since before the pandemic.
Jeurys Familia (3-1) pitched a scoreless sixth for the Mets, who also got a solo homer from Dominic Smith. Alonso ended the game by diving to catch Aaron Judge's line drive against Seth Lugo.
PLUMMETING IN PINSTRIPES
DJ LeMahieu put the Yankees up 5-4 in the fifth when he scored on Marcus Stroman's wild pitch, but the Yankees still lost for the seventh time in eight games. They dropped to 41-41 as their second half started, the latest into a season they've been at .500 since they were 56-56 on Aug. 9, 2016.
''It's another awful loss,'' Boone said. ''There's no other way to put it.''
Chapman (5-3) failed to record an out in his first appearance since giving up a tying grand slam in the ninth inning during an 11-8 loss Wednesday to the Los Angeles Angels. The flame-throwing left-hander entered with a 17.47 ERA over his previous eight outings.
Boone said Chapman erred in throwing the slider to Alonso, especially after he blew a 96.9 mph fastball by him a pitch earlier. It's unclear if Chapman will remain in the closer's role.
''We'll have to talk through that,'' Boone said.
The Mets chased Cole with one out in the third, his shortest outing since a two-inning stint on Sept. 12, 2016, while with Pittsburgh. He was charged with four runs and six hits, tying a season high with three walks.
Cole has a 5.24 ERA since it became clear in early June that Major League Baseball planned to crack down on pitchers' use of illegal foreign substances. He had a 1.78 ERA prior to that.
Boone denied Cole's and Chapman's struggles were tied to the uptick in enforcement. Cole maintains his pitches are sharp as ever despite measured drops in spin rate on his fastball and slider.
''Our metrics are telling us it's the same stuff,'' he said, adding, ''I felt that I had pretty good stuff today and the ball was moving the way we wanted.''
Cole stranded baserunners in the second and third innings, but his high-wire act fell apart in the fourth when he allowed two runs, three hits and two walks before leaving with the bases loaded and one out. Boone gave the ball to Jonathan Loaisiga, who allowed Lindor's tying RBI single before retiring Alonso with the bases loaded to preserve a 4-all tie.
Cole and Chapman were named to the AL All-Star team shortly after the final out.
Peraza's hit was reminiscent of a flyball caught by 12-year-old Yankees fan Jeffrey Maier during the 1996 AL Championship Series on a ball hit by Derek Jeter. Mets first base coach Tony Tarasco was the Orioles right fielder camped under Jeter's drive when Maier interfered.
''After the game, Tarasco was talking about fan interference at Yankee Stadium,'' Mets manager Luis Rojas said. ''I thought that was neat of him.''
The 27-year-old Peraza said he'd never heard of the play.
Mets: RHP Nick Tropeano was recalled from Triple-A to be the 27th man. ... New York activated INF Jonathan Villar (strained right calf) and started him in Game 2. OF Albert Almora Jr. was optioned to Triple-A. ... RHP Yennsy Diaz was recalled from Triple-A and RHP Sean Reid-Foley was placed on the 10-day injured list with right elbow inflammation.
Yankees: LHP Zack Britton (hamstring) will throw at least one more bullpen Tuesday before New York considers activating him. ... RHP Luis Severino, who strained his right hamstring June 12 in his second rehab appearance since Tommy John surgery, felt good after throwing a bullpen Saturday and will throw off the mound again this week. Sim games or a rehab assignment could soon follow. ... LHP Wandy Peralta was recalled from Triple-A as the 27th man.
Yankees LHP Nestor Cortes Jr. (0-0, 1.02) will start the nightcap. The Mets will turn to the bullpen, likely opening with RHP Corey Oswalt (1-0, 1.42).
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