PHOENIX (AP) -For five dominating innings, Cha Seung Baek looked as if he might become the first San Diego Padre to throw a no-hitter.

The Arizona Diamondbacks finally managed a couple of hits in the sixth. By then, the Padres were on their way to a 5-1 victory on Friday night to drop the NL West leaders below .500.

Baek knew he would have to pitch well to have a chance against Arizona's Dan Haren , the NL's Pitcher of the Month in June. Baek allowed two hits, walked one and struck out seven, matching a career high.

''Changeup, cutters, everything was working great today,'' said Baek, who won for the first time in seven starts this season.

Arizona (43-44) saw its lead over the Los Angeles Dodgers slip to a half-game, its narrowest margin since April 7. The Diamondbacks reverted to their punchless form after a dramatic 6-5 victory over Milwaukee on Thursday, when they rallied from a 5-0 ninth-inning deficit.

''We didn't look like we were rolling off the emotion of yesterday,'' manager Bob Melvin said.

The main reason was Baek (2-3), who helped San Diego win for only the third time since June 14.

Acquired from Seattle on May 28 for righty Jared Wells , Baek said he had decided after his last start to begin pitching inside.

''Today, I threw more inside pitches, and hitters get uncomfortable, then I throw outside and it worked great,'' Baek said.

San Diego manager Bud Black was impressed with Baek and rookie catcher Nick Hundley, who made his major league debut.

''Nick knew basically the foundation of Cha Seung's best stuff, and stayed with that,'' Black said.

Coincidentally, both battery mates got their first big league hits. Baek doubled to the base of the wall in center field in the third and Hundley singled in the fifth.

Baek walked Orlando Hudson with two out in the first, then retired 15 in a row.

Arizona didn't come close to a hit until Stephen Drew doubled to the gap in right-center with two out in the sixth. Justin Upton followed with a sharp single to left, but Drew was nailed at the plate on a perfect peg by left fielder Chase Headley .

For five innings, Arizona's Dan Haren (8-5) dueled Baek on even terms. But the Padres broke through in the sixth when Jody Gerut led off with a single, took third on Edgar Gonzalez 's single and scored on Brian Giles ' grounder to second base.

Gonzalez scored on a sacrifice fly to left by his brother, Adrian Gonzalez , to put the Padres ahead 2-0.

Haren allowed two runs on seven hits in seven innings, walking one and striking out seven.

Haren was disappointed in the outcome but said he felt satisfied with his performance.

''I made most of my pitches,'' he said. ''Ran into trouble there that one inning and I just tried to limit the damage. Unfortunately, they got those two runs. We closed back but it got away from us at the end.''

With the Diamondbacks down 2-0 in the seventh, Hudson greeted reliever Mike Adams with a double to right, took third on Conor Jackson 's fly to right and scored on Chad Tracy 's bloop single to left. Tracy took second on Headley's fielding error.

Black brought in Heath Bell , who retired Mark Reynolds on a foul pop and struck out Chris Young looking to keep the Padres ahead 2-1.

The Padres answered in the eighth. Brian Giles singled, took third on first baseman Conor Jackson 's throwing error and scored on a single by Kevin Kouzmanoff to take a 3-1 lead.

San Diego added two in the ninth on Edgar Gonzalez ' sacrifice fly and a single by Paul McAnulty .

Notes: Black said RHP Josh Banks would start against Arizona in Sunday's series finale. RHP Greg Maddux will pitch Monday against Florida, followed by LHP Randy Wolf and RHP Cha Seung Baek . ... Arizona RHP Micah Owings , who missed a turn with a sore gluteus muscle, made his first relief appearance of the season in the ninth. ... ... Arizona LF Emilio Bonifacio swiped third base for his first major league steal.