After some initial stumbles, the Yankees posted the best record in baseball and won the American League East by eight games before brushing aside the Twins and Angels in the first two rounds of the playoffs.

Now comes another test.

Last night’s 6-1 loss to the Philadelphia Phillies in Game 1 of the World Series put the Yankees in the unexpected position of needing to win Game 2 tonight or face the real risk of not playing at home again until next season.

“Every game in the postseason is critical,’’ said Derek Jeter, who had three of the six hits the Yankees managed off lefthander Cliff Lee. “You don’t want to lose the first two games at home.’’

Lee made the Yankees look foolish, striking out 10, including Rodriguez three times and Mark Teixeira twice. Stunned fans fled Yankee Stadium by the hundreds in the eighth inning. The Yankees did not score until the ninth, and that was on a throwing error.

“This is why you play a series. They kicked our butts today but tomorrow’s another day,’’ Johnny Damon said. “We need to get the bats going. We definitely did not expect this situation.’’

Rodriguez entered his first World Series game having hit .438 in the first two rounds with five home runs and 12 RBIs. But Lee struck him out swinging three times. Rodriguez said his approach didn’t change, only the quality of the opposition.

“I did keep it simple today. He kept it even more simple,’’ Rodriguez said. “He threw the ball well to both sides of the plate. He made his pitches.’’

Teixeira, who led the American League with 122 RBIs during the regular season, was 0 for 4 and is hitting .186 in the postseason with five RBIs over 10 games. The meat of the Yankees’ order - Teixeira, Rodriguez, and Jorge Posada - was 1 for 12 last night with seven strikeouts.

“I think Tex is going to be fine,’’ Rodriguez said. “You take tonight out of it, that’s for sure. With the exception of Jeter, we didn’t have many good swings. Teixeira has done it all year. He’s going to be just fine.’’

Yankees starter CC Sabathia did not pitch poorly. Other than two home runs by Philadelphia second baseman Chase Utley, he allowed two hits, walked three, and struck out six in his World Series debut.

“It wasn’t CC’s fault,’’ Jeter said. “He did his job.’’

As the Yankees try to recharge their offense against Pedro Martinez in Game 2, they will have erratic A.J. Burnett on the mound. He has not won this postseason.

“There’s faith in A.J.,’’ said Nick Swisher, a productive hitter who has vanished in the postseason, going 4 for 35 with one RBI. “He has the ability to shut anybody down.’’

The Yankees lost the first two games of the 1996 World Series to the Atlanta Braves, then took the next four, proof that the postseason can shift suddenly.

“Our guys will grind it out,’’ manager Joe Girardi said. “I’m not worried about that.’’