NEW YORK -- The emotions spun on a dime for Chase Headley as the Yankees' four-run eighth inning began to unfold, his stumble around first base instantly transforming the elation of having delivered a pinch-hit line drive into a clay-streaked cloud of panic.
Headley's quick thinking saved a rally that booked the Yankees' flights back to Houston, completing his dash by slamming his left hand into second base. That recovery set up Aaron Judge's game-tying double and a huge go-ahead hit by Gary Sanchez, helping the Yanks stun the Astros, 6-4, in Game 4 of the American League Championship Series presented by Camping World on Tuesday.
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"It was unbelievable. That's what baseball is supposed to be like," Headley said. "The fans were amazing. What a game."
Trailing by two runs, Todd Frazier started the eighth inning by taking a strike, then whistled a 2-1 Joe Musgrove sinker into left field for a leadoff single. Headley came off the bench to hit for Austin Romine and barreled a 2-2 cutter from Musgrove, lining it into left-center field.
Thinking double out of the box, Headley stepped awkwardly on the first-base bag and lost his footing. There was a split-second pause, he said, where he realized that shortstop Carlos Correa had not yet realized that he had fallen.
"I knew that Correa wasn't looking at me, so I knew he was going to be getting yelled at to throw the ball to first base," Headley said. "As soon as he made the throw, I'm going the other way and hopefully I can sneak in there. You've got to make the best out of a bad situation. Fortunately it worked out."
Headley slipped his hand in just ahead of a tag from second baseman Jose Altuve. Astros manager A.J. Hinch saw the play, confirmed by a review, as the key to the inning. Hinch said that "it set up a ton of pressure on us for the rest of the inning, with guys all over the place."
And the math shows just how big the play really was. According to a win-expectancy matrix created by MLB.com's Tom Tango, the Yankees' win expectancy was 23 percent when Headley stepped to the plate. Had Headley been tagged out, the Yanks' win percentage would've dropped to 22 percent.
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When second-base umpire Jim Carlson signaled that Headley was safe, the Yankees' chances of winning Game 4 jumped to 46 percent.

"You don't want to see your guy tripping; I've been there," Didi Gregorius said. "He was in no-man's land. I think he kind of deked Correa. That just got the dugout more hyped up. It got the team going. That shows everything right there."
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Houston called upon closer Ken Giles, but Brett Gardner knocked home New York's third run with a ground ball to the right side, setting up Judge with one out and the tying run 90 feet away in pinch-runner Jacoby Ellsbury.
Recognizing that a fly ball would have tied the game, Giles threw four straight sliders to Judge, running the count to 2-2, before Judge fouled off a fastball. Giles went back to an 86-mph slider, but he left it up enough for Judge to dent the left-field wall with a game-tying double.

"You just try to go after the mistakes," Judge said. "Tonight I was able to get a couple of mistakes and do some damage with them."
Gregorius followed with a seeing-eye single to left field, putting runners at the corners for Sanchez, who has struggled mightily this postseason, having fared 0-for-13 in the ALCS entering the at-bat. Those frustrations evaporated as Sanchez's eyes widened for a 2-0 fastball, crushing Giles' 98.6-mph offering into right-center field.
"When I got to second base, my emotions were through the roof," Sanchez said through an interpreter. "When I looked around and saw the fans cheering and screaming, it's nice to see all their support to come out here. It's amazing."

The ball left Sanchez's bat at 113.1 mph, making it the hardest-hit ball of the game for either team, per Statcast™. It was the second-hardest hit of the postseason behind Cubs outfielder Kyle Schwarber (114.8 mph).
"When Judge hit the double and Gary hit the ball to right-center, the place was just electric," Gardner said. "It was one of the most fun innings I've ever been a part of."
Luke Gregerson worked his way out of a bases-loaded jam to prevent any more damage, getting Aaron Hicks and Frazier to ground out, but the damage was done.
"I think we've shown all year that we don't quit. We keep playing," Headley said. "We have a lot of fun and a lot of confidence in our ability. Even though we hadn't been hitting to that point, it was just a string of good at-bats. Guy after guy, doing his job."