CHICAGO -- Derrek Lee refused to take his birthday off.
Lee has homered on four straight birthdays, and has five home runs in his career on his birthday.
"He wasn't going to play today, but he kind of pleaded with us that he always hits home runs on his birthday, so I guess I have to listen to him. That was a big one," Baker said.
Chicago trailed 2-1 in the eighth against John Grabow (4-2) when pinch-hitter Angel Pagan, Juan Pierre and Ryan Theriot loaded the based with singles.
With one out, Lee connected off Matt Capps for his seventh career slam, his first since Aug. 24, 2004, against Milwaukee. Henry Blanco and Angel Pagan added RBI singles in the six-run inning.
Lee can't understand why he has so much success on his birthday.
"It's just a fluke, there is nothing," Lee said.
He broke two bones in his right wrist in a collision with Rafael Furcal of the Dodgers on April 19. He was activated on June 25 but experienced pain and weakness in the wrist and was placed back on the disabled list on July 24. Lee was activated again on Aug. 28.
"I feel good," he said. "I'm seeing the ball good. I feel like I'm hitting the ball hard more consistently now, and that's all I try to do, is hit the ball hard."
Michael Wuertz (2-1) got two outs in the eighth to win in relief of Rich Hill, who struck out 11 in 7 1/3 innings. Hill set a team record for strikeouts by a left-hander, topping Steve Wilson's 10 on July 15, 1990, against the Los Angeles Dodgers.
Chicago passed Pittsburgh and moved out of last place in the NL Central, ending its five-game losing streak to the Pirates.
Pirates starter Zach Duke allowed one unearned run and six hits in seven innings.
"Our guy was terrific," Pirates manager Jim Tracy said. "Really they shouldn't have scored a run off of him in the seven innings that he pitched. It was one of his better games of the year. He had it all working."
Ronny Paulino's passed ball allowed Ronny Cedeno to score from third base in the third.
Pittsburgh rallied for a 2-1 lead in the eighth. Hill threw wildly on pinch-hitter Jack Wilson's bunt single for a run-scoring error and the Pirates got another run on an RBI grounder to shortstop by Jose Bautista in which Cedeno threw wildly to the plate for another error.
Pittsburgh SS Jack Wilson continues his recovery from an inner ear infection. Tracy thinks Wilson could make his return to the starting lineup on Saturday when the team travels to Cincinnati. Wilson has missed 12 straight starts. ... With runners on first and third and one out in the sixth inning, Cubs 3B Aramis Ramirez hit a hard grounder behind the bag at second, SS Freddy Sanchez made a diving stop and flipped it from his glove to 2B Jose Castillo, who barehanded it and threw to first to complete the double play.