SAN FRANCISCO - Roy Oswalt will have to overcome a rib injury and Barry Bonds to become the first 19-game winner in the National League.

Oswalt and the Houston Astros will look to gain ground in the wild-card race when they continue their three-game series with the San Francisco Giants.

San Francisco currently leads the wild-card race by a half-game over the Chicago Cubs and two over Houston with 11 games to play.

The Astros have won 19 of 24 to move within striking distance of the Giants.

Oswalt’s stellar second half has played a big role in Houston’s turnaround. The 27-year-old right-hander is 10-2 with a 3.22 ERA in 14 starts since the All-Star break.

However, Oswalt aggravated a rib cage injury on Friday in a 2-1 win over Milwaukee. He stayed in long enough to get the win, allowing eight hits and two walks while striking out five over seven innings. He said the injury has bothered him all year and he has taken three cortisone shots and three Novocain shots.

“It’s just something you deal with,” Oswalt said. “Hopefully, we can try the painkiller again next time and get me through it. It takes your breath away as soon as you release the ball. I’ve been doing the cortisone shots and I don’t want any more of them. Hopefully, the Novocain shots will be enough next time.”

Oswalt (18-9, 3.48 ERA) is currently tied with teammate Roger Clemens for the NL lead with 18 wins. His next win will tie his career high, set in 2002. He is 1-1 with a 3.98 ERA in four career starts against the Giants.

Bonds has owned Oswalt throughout the right-hander’s four-year career, going 3-for-3 with two doubles, a homer and two walks.

Bonds took a back seat to his teammates Tuesday.

Pedro Feliz matched his career high with four RBIs, and Brett Tomko won his sixth straight decision as the Giants cruised to a 9-2 victory over the Astros.

Bonds went 0-for-3 with a walk as the Giants moved within a game and a half of first-place Los Angeles in the NL West.

Giants starter Noah Lowry (5-0, 4.09 ERA) has allowed only two runs over his last 13 2-3 innings in winning back-to-back starts. The 23-year-old left-hander held limited San Diego to one run and five hits over 6 2-3 innings in a 4-1 win on Friday. Lowry is unbeaten in 18 major league appearances, including 12 starts.

Streaks and notes: Astros - OF Berkman has walked a career-high 125 times. He has 93 strikeouts. ... Houston is 8-23 against San Francisco since 2000. ... OF Beltran is mired in a 1-for-19 slump. Giants - INF Feliz is 3-for-6 with a triple and home run against RHP Oswalt. ... OF Bonds leads the NL with a .369 batting average. ... San Francisco is 12-5 in September.