One by one, the dominoes fell for the Yankees Wednesday in their quest to clinch the American League East title:

First, they beat the Rays, 4-2, in the first game of a day-night doubleheader at Yankee Stadium to secure a playoff berth.

Second, the reeling Red Sox lost to the Orioles, 6-4, Wednesday night at Fenway Park.

Finally, pinch hitter Jorge Posada's two-run single in the eighth inning drove in the go-ahead runs as the Yankees won the nightcap, 4-2.

Rafael Soriano -- closing the game instead of Mariano Rivera, who got the save in Game 1 -- struck out Matt Joyce to end Game 2 at 11:07 p.m.

The Yankees had a subdued celebration on the mound, with a little more hugging than their usual congratulatory conga line. The real party would come in the clubhouse, where they enjoyed the usual champagne-soaked scene as they donned AL East champion hats and T-shirts.

When asked about his hit, Posada said, "I wouldn't say it was an all-time moment. But it's a pretty big moment for me, yes."

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In spring training, Brian Cashman said the Red Sox won the offseason. The Yankees won the regular season.

"It's not often that we're considered the underdogs, but I understood with the moves that they had made," Joe Girardi said. "But this group has a lot of pride. This is a special group that knows how to win and knows how to bounce back when things are tough. They don't panic."

Now, for the Yankees at least, comes the postseason beginning Sept. 30. It remains to be seen if the Red Sox will join them. Boston leads the Rays and Angels by 2½ games for the wild card. The Yankees have helped out the Red Sox immensely by taking the first three games of this series against Tampa.

All that is left for the Yankees to accomplish in the regular season is to clinch home-field advantage throughout the American League playoffs. That and getting through the final seven games without suffering any injuries -- plus getting their regulars rested and pitchers lined up for a first-round series against the Rangers, Tigers or Angels.

In a season that has included Derek Jeter's 3,000th hit and Rivera's setting the all-time saves record, the next personal milestone was CC Sabathia winning his 20th game.

In his third try, the Yankees' ace went 71/3 innings in Game 2 and left with the score tied at 2. He also left with the bases loaded, but David Robertson threw one pitch and got Ben Zobrist to bounce into an inning-ending, 4-6-3 double play.

The Yankees staked Sabathia to a 2-0 lead on a home run by Robinson Cano and a run-scoring double play by Jesus Montero. But home runs by Kelly Shoppach in the fifth and Sean Rodriguez in the seventh tied the score at 2.

Posada was batting for Montero when he smacked the two-out, two-run single to right in the eighth off Brandon Gomes after an intentional walk to Cano loaded the bases. It was a blast from the past for Posada, the 40-year-old Yankees icon who is trying to win a spot on the postseason roster.

Jeter was thrilled for his old friend.

"He takes a lot of pride in going out there and doing his job,'' Jeter said. "He hasn't been on the field as much as he's used to, but in that situation, I knew he was going to get a hit."

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Said Girardi, "I'm sure it meant a lot to him. This is a guy who has been a great Yankee and has had a lot of big hits in his time. Just to get another one to clinch the division has to mean a lot to him. We went through some difficult struggles at times, but I believe in Jorgie."

In the opener, Cano's two-run, eighth-inning double snapped a 2-2 tie as the Yankees -- who used eight pitchers after Phil Hughes was scratched with back issues -- earned a playoff berth for the 16th time in 17 seasons.

Game 2 was delayed one hour and two minutes at the start by rain. For the Yankees, it was definitely worth the wait.