Jon Lester pitched eight dominant innings, and the AL East-leading Boston Red Sox dealt the New York Yankees' wild-card hopes another blow with a 5-1 win on Saturday.
Mike Napoli, Jonny Gomes and Shane Victorino each had two hits as the surging Red Sox won for the 16th time in 19 games and beating the Yankees for the fifth time in six meetings in just over a week.
The Yankees lost their second straight after a three-game winning streak and fell 2½ games behind Tampa Bay for the AL's second wild-card spot. The Rays play at Minnesota on Saturday night.
Boston entered the day with an 8½-game lead over second-place Tampa Bay.
The Red Sox (91-59) improved to a season-high 32 games over .500, their best mark since the final day of their World Series championship season in 2004.
Lester (14-8) was solid from the start, mixing a sharp cutter with a well-spotted, mid-90s fastball. He allowed one run and three hits, striking out five and walking two for his fourth win in six starts.
Franklin Morales worked a perfect ninth.
For the second time in week, Boston goes for a sweep against New York. Last weekend, the Red Sox won the initial three of a four-game set at Yankee Stadium but lost the finale.
The Red Sox built a 5-1 lead against CC Sabathia (13-13) after five innings.
Will Middlebrooks' run-scoring grounder gave Boston a 1-0 edge in the second. Napoli singled before moving up on a walk and sacrifice.
In the third, David Ortiz had an RBI double and Gomes added a run-scoring single. Sabathia then fanned the next two hitters with runners on first and third.
Lester breezed through the first nine batters, holding the Yankees hitless before Curtis Granderson tripled off the center field wall leading off the fourth. He scored on Robinson Cano's bouncer to first to make it 3-1. But Victorino had a two-out RBI single in the bottom half.
Sabathia went six innings, allowing five runs on nine hits, walking four and striking out five. He's 4-6 with a 6.48 ERA in his last three seasons against the Red Sox.
Daniel Nava's sacrifice fly increased it to it 5-1.