Three San Diego pitchers combined on a six-hit shutout and an eighth-inning bunt single by Tony Gwynn Jr. led to the only run as the host Padres defeated the Houston Astros 1-0 on Saturday night.

Pinch hitter Aaron Cunningham led off the eighth inning with a double and Gwynn followed with a bunt down the third-base side. Houston pitcher Gustavo Chacin (1-1) fielder the ball and threw wildly to first, allowing Cunningham to score easily.

The Padres have shut out Houston each of the past two nights. Saturday’s blanking was San Diego’s major-league leading 12th of the season.

Heath Bell struck out Lance Berkman and Carlos Lee as part of a scoreless ninth to record his 23rd save. Reliever Mike Adams (2-1) pitched a perfect eighth for the victory.

Starting pitchers Bud Norris of Houston and Kevin Correia of San Diego were part of an unexpected pitcher’s duel as both turned in seven shutout innings.

Norris allowed three hits and three walks. He struck out five while lowering his earned-run average to 5.98.

Correia gave up five hits and two walks. He struck out four and dropped his ERA to 5.05.