Updated

The Boston Red Sox try to put even more distance between themselves and the Baltimore Orioles on Thursday when the American League East foes close out a three-game set from Fenway Park.

Boston has won the first two games of this series and is now 7 1/2 games in front of the Orioles in the division.

Completing the sweep may not be that hard, as Red Sox starter Jon Lester owns a lifetime mark of 15-2 against the Orioles with a 2.72 ERA in 23 starts. The 15 wins are his most against any team.

Lester has been terrific over his last two starts, giving up just one run in 15 2/3 innings. He won his second straight start on Saturday in Los Angeles, as he held the red-hot Dodgers to just a run in 7 1/3 frames to run his record to 12-7, while lowering his ERA to 3.97.

"He's just getting more comfortable," Red Sox catcher Jarrod Saltalamacchia said. "I think he was messing with mechanics a little bit and going back and forth with different stuff, as we all do. The biggest thing for him is getting ahead, first-pitch strikes and focusing on attacking the strike zone."

On Wednesday, pinch-hitter Mike Carp's RBI single in the eighth inning lifted Boston to a 4-3 win. Shane Victorino added an RBI single for the Red Sox, who have won four in a row and lead the Tampa Bay Rays by 2 1/2 games for first place in the AL East.

Boston starter John Lackey allowed three runs on seven hits over 7 1/3 innings. Craig Breslow (4-2) recorded the final two outs in the eighth to pick up the win.

Chris Davis hit his MLB-leading 47th homer of the season and knocked in two runs for the Orioles, who are now 4 1/2 games back in the wild card chase.

Bud Norris got the start for Baltimore and gave up one run on four hits while striking out seven and walking four over 5 1/3 innings. Tommy Hunter (3-3) allowed one run on two hits in the eighth to take the loss.

"I battled hard and that's a good ball club over there, you have to tip your hats to them," said Norris. "We just didn't get the bounces we needed today."

Getting the call for the Orioles on Thursday will be righty Chris Tillman, who will take his fifth shot at nailing down win No. 15. Tillman, though, has pitched well in his last four starts with a 2.57 ERA, but the O's have backed him with just nine runs in those outings.

That was the case on Saturday against Oakland, as Tillman surrendered just a run in eight innings, but did not factor in the decision of the O's 2-1 loss. He is 14-4 on the year with a 3.66 ERA.

Tillman has faced the Red Sox eight times and is 3-1 with a 2.08 ERA.

Boston has split its 12 meetings with the Red Sox this season.