CHICAGO — Ryan Dempster isn't ready to shut it down.

Dempster pitched a five-hitter for his third career shutout, Jeff Baker had a two-run double and the Chicago Cubs beat the Pittsburgh Pirates 6-0 on Tuesday night.

Derrek Lee added a two-run single for the Cubs, who have won seven of nine but were eliminated from the playoff race when the Colorado Rockies beat Milwaukee later Tuesday.

The Cubs (82-74) guaranteed a winning record for the third straight season. It's only the second time in the last 70 years the Cubs have had three or more consecutive winning seasons.

Dempster struck out six and walked two. He retired the ninth inning to record his first shutout since July 3, 2001, against the Montreal Expos, when he was a member of the Florida Marlins.

"It's unfortunate the season is coming to an end because I feel stronger than I did earlier in the year," Dempster said.

Pirates starter Kevin Hart (4-9) made his second start against his former team since being acquired from the Cubs in a five-player deal July 30. The troubles continued from the first inning for Hart, who is 1-8 in 10 starts since being acquired from the Cubs.

Ryan Theriot led off the first inning with a walk off Hart, then went to third on Kosuke Fukudome's double. One out later, Micah Hoffpauir hit a bouncer to first baseman Garrett Jones. Jones made a low a flip to Hart, who was running to first to cover the base but Hart dropped the ball and was charged with an error as Theriot scored. Baker followed with a two-run double to give the Cubs an early 3-0 lead.

After Pirates second baseman Delwyn Young committed the Pirates' third error of the game to load the bases in the fourth inning, Lee hit a two-run single and Hoffpauir drove in a run on a fielder's choice.

"We played terrible behind him. He was misfiring, but he battled. We make some plays, it's a lot different line score for him," Pirates manager John Russell said.