"I was just hoping it was out of the park so we wouldn't have to keep playing," Posada said. "I didn't want to play anymore. It was a long game."
Posada's homer capped the wild, three-hour, 49-minute game which featured 34 hits, 11 walks, two hit batsmen and two errors.
The Yankees overcame an early 10-1 deficit, tying the franchise record for the largest comeback in a game.
"It's hard to beat that one," said manager Joe Torre. "It was such a team effort all the way around. I can't be more proud of the way this ballclub responded tonight. They fought hard, which is what they've done all year."
"Possible? Yes. Realistic? You'd have to think about that for a minute," Johnny Damon said when asked if he thought a comeback was possible at 10-1. "There's a lot of heart here. A lot of people doubted us with [Gary Sheffield], [Hideki] Matsui and [Jason] Giambi out, but we kept bringing it."
Derek Jeter went 4-for-5 with a home run and four RBIs, while Posada, hitting cleanup for the first time since Oct. 2, 2004, finished the night with five RBIs of his own.
"This says a lot about this team and about the guys," Posada said. "We did a lot of things right, we did a lot of things wrong, but we kept fighting."
Things didn't look good early on for the Yankees, as Texas tagged Shawn Chacon for eight runs on six hits and two walks in just 1 1/3 innings.
"Did he start tonight? I don't even remember, it was such a long time ago," cracked Torre after the game. "He got himself in trouble, pitched from behind and threw a lot of pitches early. When he tried to make a pitch, he didn't make it."
Aaron Small relieved Chacon in the second, promptly serving up a three-run homer to Hank Blalock on his third pitch, giving Texas a 9-0 lead.
With the score 10-1 after the top of the third, the Yankees started chipping away at starter John Koronka. Jeter and Posada each drove in runs to cut the lead to 10-3 in the third, then Posada and Robinson Cano added RBIs in the fifth, slicing the score to 10-5.
"You have to think small," Jeter said. "We had a long way to go, so you try to score one at a time, not try to get them all back at once."
"Once we stabilized them, then we score a run or two and they don't get it back, you're five runs back and it's realistic," Torre said. "I think everybody sensed that."
Posada helped hold the Rangers from extending their lead in the sixth, tagging Mark Teixeira out at the plate after a violent collision.
"That's probably the hardest I've ever been hit," Posada said. "I've never played football in my life, but that's probably what it feels like."
"He looked a little dazed, but he kept answering the questions the right way," Torre said when asked if Posada came close to leaving the game. "He seemed to have his senses about him."
The Yankees completed their first comeback in the sixth, scoring six times to take an 11-10 lead. Jeter's three-run homer brought New York within two runs, while Miguel Cairo's two-run single capped the rally, sending the 40,757 fans into a frenzy.
The euphoria didn't last long, though, as Scott Proctor walked Kevin Mench to start the seventh, setting up Brad Wilkerson's two-run homer, which gave the Rangers the lead once again.
Following the pace of this game, the Yankees wasted no time in tying it up. Damon reached on an error, moved to third on Jeter's bunt single and another Rangers error, then scored on Posada's sac fly. But the Yankees couldn't move the go-ahead run home from third, sending the game into the eighth tied at 12.
Closer Mariano Rivera entered the tie game in the ninth, and Mench blooped a broken-bat single to center to start the inning. Wilkerson bunted pinch-runner Adrian Brown to second, then Rivera walked Mark DeRosa, putting men at first and second.
Rod Barajas followed with a broken bat double down the third-base line, scoring Brown to put the Rangers back in the lead. Rivera got out of the inning without any further damage, giving the offense one final chance to pull out the win.
"You can't do anything against that," Rivera said. "When you have hits like that, bloops, you just have to continue to battle. I was disappointed, but you can't control it."
As the Yankees walked toward the dugout, Torre sent a message to Posada and his teammates.
"Skip said, 'This game is yours. You fought too hard to lose it,'" Posada said. "We kept coming. It was just meant to happen."
Damon reached base with a single, moving to second on Jeter's groundout. Alex Rodriguez lined out to center, bringing Posada to the plate. Otsuka fell behind, 3-0, then threw a strike to Posada. One pitch later, Posada crushed Otsuka's 3-1 offering into the front row of the right-field bleachers, capping the win.
"We just have one way we like to believe we do things; to get the most out of every at-bat, play every single inning, and when it's all said and done, let's see where we are," Torre said. "It was a big lift, to let us know what we're capable of doing."
"It was a great game for him," Damon said. "He saved a run at the plate by holding on to the ball, hit the two-run homer. He sent a lot of people home happy."