Before Boston turned to closer Jonathan Papelbon in the top of the ninth, Toronto's lone run came on Jose Bautista's first-inning homer.

Lester (15-5) walked two batters and struck out six.

Papelbon earned his 38th save despite giving up two runs and three hits.

Three Toronto players had one RBI.

Lyle Overbay had two of the seven hits for the Blue Jays, who have lost three of four.

Losing pitcher Roy Halladay (18-11) surrendered three runs -- two earned -- and six hits in seven innings with no walks and five strikeouts.

With the win, the Red Sox closed to within one game of American League East-leading Tampa Bay.

The Rays suffered an 8-4 loss to the New York Yankees.