CHICAGO -- Jon Lester recovered from a rut of bad starts, pitching six shutout innings that led the Chicago Cubs over the Seattle Mariners 12-1 Friday for their third straight win.

Jason Heyward and David Ross homered as the NL Central leaders improved to 9-5 since the All-Star break following a 1-9 slump. Seattle lost in its first trip to Wrigley Field since 2007.

Lester (11-4) had lasted just 16 innings over his previous four starts, going 1-1 with a 10.13 ERA. That skid came after he had gone 9-3 with a 2.03 ERA in his first 16 starts.

Lester gave up four hits, struck out seven and walked two. He was already done when there was a 74-minute rain delay in the seventh.

Mike Montgomery, traded last week from Seattle to the Cubs, pitched the final two innings. He gave up a single to Shawn O'Malley in the ninth for the Mariners' run.

Hisashi Iwakuma (11-7) had won his last five starts, but gave up five runs and eight hits in three innings.