Larry Bowa touched off a five-run sixth inning by singling home Keith Moreland as Chicago beat visiting San Diego.
The Cubs, winning only their fifth game in their last 17, had six singles in the inning, all off reliever Gary Lucas (4-6).
With one out, Moreland singled to left and took second on a wild pitch. Jody Davis beat out an infield hit as Moreland took third and Moreland scored on Bowa's sharp single to left. Reliever Craig Lefferts then bunted for a single to load the bases.
Mel Hall grounded off third baseman Luis Salazar and the ball bounced to shortstop Garry Templeton, who attempted to force Davis at the plate, but overthrew catcher Terry Kennedy as two runs scored. Lefferts moved to third and Hall to second on the error and both scored on Ryne Sandberg's single.
"Larry Bowa's hit gave us the lead but Lefferts' bunt set things up for us to break the game wide open," said Manager Lee Elia, who explained that he allowed Lefferts to bat for himself. "We had a 3-2 lead, there was only one out and the way things have been going for us lately in the bullpen we're trying to use as few people as possible."