Dickie Noles, the last Chicago pitcher to lose a game, pitched and batted his team to victory over visiting Pittsburgh.
Noles (9-12) doubled and scored a run to support his five-hit pitching during his seven innings. He struck out a season-high eight and walked two.
"It was nice to come back," said Noles, observing that he felt "like part of the team again."
The victory was the fifth straight for the Cubs and sixth in seven games. They last lost Tuesday, a 15-5 embarrassment to Noles in Pittsburgh.
The Pirates fell into fourth place in the NL East, 7 1/2 games behind the first-place St. Louis Cardinals. Pittsburgh Manager Chuck Tanner called Noles' performance superb.
"He had the best stuff I've ever seen him have," Tanner said.
The Cubs broke a scoreless tie in the fourth inning after Pirate pitcher Larry McWilliams (7-8) gave up his only walk of the day, to Keith Moreland. Moreland went to second on a wild pitch and scored on Jerry Morales' single to left.
The Cubs made it 2-0 in the fifth when Junior Kennedy singled and scored when Gary Woods doubled off the left field wall.
Jim Brady, the White House press secretary, threw out the first ball in the game and was awarded the No. 1 card in the Cubs' "Die-Hard Fan Club." Brady, a longtime Cub fan, became one of 15,000 Cubs fans worldwide who have joined the club this year.