SAN DIEGO -- Tony Gwynn Jr. started growing a beard at the beginning of June and doesn't plan to shave it until he lifts his batting average to .250.

He took a slight step backward on Sunday, but it was worth it.

After going hitless in his first four at-bats, Gwynn hit a bases-loaded single up the middle against a drawn-in infield with one out in the ninth inning to give the San Diego Padres a 3-2 win against the Houston Astros on Sunday.

Gwynn's average dipped from .228 to .227.

"I don't know how much longer my face can take it, but I'm going to roll with it as long as I can," said Gwynn, the leadoff batter and center fielder.

Gwynn helps the Padres in different ways than his father, the Hall of Famer who had 3,141 hits and a .338 lifetime average in his 20-year career in San Diego.

On Saturday night, an eighth-inning bunt went for an infield single and contributed to the winning rally. Earlier in Sunday's game, Gwynn made a diving catch of Brett Myers' fly ball.

"Tony's had a good couple of games in the areas where he needs to have them, in bunting and defense," Padres manager Bud Black said. "I think his average will climb as we move into the second half."

Yorvit Torrealba started the winning rally when he singled to right on Brandon Lyon's first pitch of the ninth. Aaron Cunningham, who hit a two-run single in the fourth, sacrificed, Everth Cabrera was intentionally walked and pinch-hitter Matt Stairs walked to load the bases. Gwynn then swatted a first-pitch fastball up the middle.

"Typically when the infield's in, your best friend is up the middle," Gwynn said. "Having faced Lyon a couple of nights ago I had an idea of what I wanted to do. I got a pitch to handle and it was able to work out for me."

It was the Padres' 11th win in their final at-bat at home and their third straight. The Padres took three of four from the struggling Astros.

Gwynn said he took some good swings even though he didn't have anything to show for them until the ninth.

"I think anybody can deal with a hitless game if they come up with a chance to help a team win a ballgame," Gwynn said. "If you can come through, you can forget about the other four at-bats you had before and you're able to digest that one hit you had. Fortunately I was able to have that last opportunity and I was able to come through."

In that situation, "You've dug a hole anyway," Lyon said. "The chances of coming out of it aren't great but I feel like I have the mindset to get out of it.

"I can't say it was a bad pitch," Lyon said of the fastball to Gwynn. "If I could take it back, I probably wouldn't throw that pitch. I'd probably throw it farther in."

The NL West-leading Padres (49-33) are 16 games above .500 for the first time this season.

Houston's Lance Berkman homered in the first inning and tied the game with an RBI triple in the eighth.

"This was a tough series because we should have won that game today," Berkman said. "We gave them the game. It's tough to come in with their pitching staff because you know they're going to be low-scoring games. Your defense is critical and we made some mistakes."

Heath Bell (4-0) pitched a perfect ninth for the win. Lyon fell to 5-3.

After getting shut out on Friday and Saturday nights, the Astros scored first when Berkman homered to left on an 0-2 pitch from left-hander Wade LeBlanc with one out in the first. It was his eighth overall and first from the right side this season.

The Astros failed to turn a routine force play that would have ended the fourth and it ended up costing them the lead when Cunningham hit a two-run single.

Myers retired the first two batters before allowing a single by Scott Hairston and walking Chase Headley. Torrealba hit a grounder deep in the hole to shortstop Oswaldo Navarro, who hesitated before throwing to second and Headley was called safe, loading the bases.

Cunningham followed with a single that fell in just in front of left fielder Carlos Lee to bring in Hairston and Headley.

Cunningham scored the winning run in Saturday night's 1-0 victory.

The Astros tied it in the eighth against Mike Adams when Jeff Keppinger hit a leadoff single to right and scored on Berkman's triple off the right-field wall.

Myers went six innings, allowing two runs and four hits. He extended to 17 his franchise record for consecutive starts of six-plus innings to begin a season.

LeBlanc allowed one run and three hits in 6 2/3 innings, walked three and struck out two.

• Astros OF Michael Bourn and Padres 1B Adrian Gonzalez were picked to the NL All-Star team. It is Gonzalez's third time and Bourn's first.
• San Diego closer Heath Bell is one of five players on the ballot for the NL's Final Man.
• Houston's starters allowed only three earned-runs in 25 2/3 innings during the series for a 1.05 ERA.