BOSTON (AP) - Jacoby Ellsbury studied Andy Pettitte 's slow windup. He took a few steps toward home. Then he took off.

The Red Sox speedster slid headfirst, stirred up a cloud of dirt and looked at plate umpire Gary Cederstrom.

Safe.

''The biggest thing is getting the courage to go, I guess. In that situation, bases loaded, you've got to make it,'' Ellsbury said after a 4-1 win Sunday night gave the Red Sox their 10th straight win and a three-game sweep of the New York Yankees . ''I was pretty confident that I could get in there.''

His first steal of home since before college came in a three-run fifth inning after New York's Brett Gardner and Boston's David Ortiz hit sacrifice flies in the third.

Ellsbury decided to run after watching the left-hander's previous pitch. Batter J.D. Drew didn't know that but, as a left-handed hitter, saw him running and sliding under Jorge Posada 's swipe.

So did Pettitte.

''Obviously, that's frustrating,'' Pettitte said. ''I was in the windup. I should have been in the stretch. Jorgie told me to keep an eye on him. I saw him in the corner of my eye and tried to speed up my windup.''

The Red Sox came from behind in all three games, went 9-0 on the homestand and are 12-6 after starting at 2-6.

''I don't want to get carried away with what happened in this homestand,'' Boston manager Terry Francona said. ''but it was a good homestand.''

In the fifth, Ortiz doubled in the go-ahead run before Kevin Youkilis was walked intentionally to load the bases. As Pettitte began his windup with third baseman Angel Berroa playing far off the bag, Ellsbury ran.

''There was no set play so I originally was going to go feet first. But then I saw J.D. kind of move that he saw me coming in, so at the last minute I decided to go headfirst,'' he said. ''I was just hoping J.D. wasn't going to swing at a pitch right down the middle and hit me.''

When he did swing, he hit a ground-rule double that made it 4-1.

Justin Masterson (2-0) pitched 5 1-3 innings in his second start in place of Daisuke Matsuzaka , who is on the disabled list. Takashi Saito pitched the ninth for his second save.

Pettitte (2-1) dropped to 17-2 in 24 starts when trying to prevent the Yankees from getting swept, according to Elias Sports Bureau. The Yankees fell to 9-9.

''For me to get concerned is going to take a lot more than that,'' Pettitte said.

Ellsbury's steal was the latest dramatic play in the series.

The Red Sox won 5-4 Friday night when Jason Bay tied the game with a two-run homer off Mariano Rivera in the ninth and won it on Youkilis' homer in the 11th.

Boston won 16-11 on Saturday, overcoming a 6-0 deficit with six RBIs from Mike Lowell in the seventh and eighth.

On Sunday, Pettitte struck out the side in the fourth. But in the fifth, he walked Jason Varitek , struck out Nick Green and walked Ellsbury. The runners stayed put on Dustin Pedroia 's fly out.

Ortiz doubled off the left-field wall, scoring Varitek and sending Ellsbury to third. Youkilis, who began the day with a major-league best .444 batting average, then was walked so Pettitte could face Drew, who already had struck out twice.

He should have paid more attention to Ellsbury.

''It shouldn't happen, but it did,'' said Yankees manager Joe Girardi , who tried to alert Pettitte as the crowd roared. ''We were screaming, but nobody can hear you here.''

Notes: Derek Jeter tied Mickey Mantle for the Yankees record of 8,102 career at bats when he struck out in the seventh. ... Johnny Damon got the day off until he flied out as a pinch-hitter to end the game. Yankees manager Joe Girardi said his knee, shoulder and back are ''a little banged up.'' . ... Capt. Richard Phillips of the cargo ship Maersk Alabama threw out a ceremonial first pitch. The resident of Jericho, Vt., spent five days as a hostage of Somali pirates. Jack Parker, coach of NCAA hockey champion Boston University also threw out a ceremonial pitch. ... Robinson Cano extended his hitting streak to 13 games. Lowell's reached 10.