"It's hard to believe," Yankees manager Joe Girardi said. "We kind of got a gift tonight."
David Wright had put the Mets ahead 8-7 with an eighth-inning double off Mariano Rivera (1-2), and Francisco Rodriguez (1-1) appeared to escape a ninth-inning jam on the popup by A-Rod, just 1 for 17 in his career off K-Rod, including the postseason.
But Castillo allowed the ball to pop out of his glove as he tried for a one-handed catch on the right field grass. The Yankees ran onto the field as Derek Jeter scored from second and Mark Teixeira from first.
"We'll have to fight through this," Mets manager Jerry Manuel said. "This is definitely a tremendous test for us."
Jeter had singled with one out and stole second as pinch-hitter Johnny Damon struck out on the ninth pitch. Teixeira was intentionally walked and Alex Rodriguez got ahead 3-0 before taking a strike and then popping up.
Teixeira ran hard from first the entire way and easily beat the throw. It was the first blown save by K-Rod in 17 chances this season.
On a night the Mets brought some real energy to Yankee Stadium, known thus far for home runs and empty premium seats, the crowd of 47,967 was the largest since opening day but again short of a sellout. Fans saw five more home runs at the Bronx bandbox, raising the total to a major league-leading 110 in 30 games.
Gary Sheffield homered for the Mets, and Robinson Cano, Teixeira, Jeter and Hideki Matsui connected for the Yankees, who wasted leads of 1-0, 3-2 and 7-6 before winning. Matsui turned 35 and homered on his birthday for the second straight year
- last year he hit a grand slam off Oakland's Joe Blanton.
Rivera made a rare eighth-inning appearance in a tie game when he relieved with two outs and the score 7-7.
Carlos Beltran reached on just the third walk off Rivera in 26 2-3 innings this year. With the count 2-2, Beltran took off for second and Wright turned on a pitch over the middle of the plate. The ball hit the wall in right-center on a hop, and Beltran scored without a throw as Rivera hung his head and grimaced. Wright is hitting .633 (19 for 30) in his last eight games, raising his major league-leading average to .364.
The Yankees have dominated their Queens rival since interleague play began in 1997, going 37-29 against the Mets during the regular season and winning the 2000 World Series in five games.
But with new ballparks, the Subway Series had a new look this year. And both teams were eager to get back on track
- while the Yankees stumbled as they got swept in Boston, the Mets lost two of three at Citi Field to the Philadelphia Phillies.