San Diego, CA -- (Sports Network) - Jody Gerut had three hits, including the game-winning RBI single in the eighth, as San Diego defeated Arizona, 5-4, to complete a three-game sweep of the NL West-leading Diamondbacks.

Nick Hundley hit a two-run homer while Edgar Gonzalez and Chase Headley had RBI singles as part of San Diego's five-run comeback. Mike Adams (2-3) got the win with a scoreless eighth frame. Padres starter Cha Seung Baek lasted 5 2/3 innings in the no-decision after giving up two runs on six hits and one walk with three strikeouts to remain winless over his last four starts.

San Diego, playing the role of spoiler, swept the D'Backs with wins against Dan Haren and NL Cy Young Award candidate Brandon Webb before besting future Hall-of-Famer Randy Johnson. The Padres entered the series on a seven-game skid and hold the National League's second-worst mark at 51-82.

"At this point, we're probably just going to be spoilers here. We're going to make other teams sweat a little," Gerut said of San Diego's sweep. "The last thing we want to do is have people come in and think we're pushovers. I think this series is a good message that we're going to continue to fight."

Despite the sweep, Arizona continues to hold a three-game advantage in the NL West by virtue of the LA Dodgers' current, season-long six-game skid. The Dodgers continued their slide with a 5-4 setback to Washington Wednesday.

Johnson received his second straight no-decision after winning six of eight starts and remains six wins shy of becoming the 24th pitcher to reach 300 wins. The veteran lefty allowed three runs on five hits and one walk while fanning nine in seven innings. He also contributed at the plate, going 2-for-3 with an RBI single.

Miguel Montero, Chris Young, and Mark Reynolds also knocked in a run each as part of a four-run sixth. The D'Backs, who have lost four straight and five of their last six, have had the bullpen register losses in three of those games.

Chad Qualls (2-8) came on for Johnson in the eighth and was greeted by a single from Brian Giles, who moved to second on a sacrifice. Headley tied the game with an RBI single to right two batters later, stole second and scored the go-ahead run on a single to right from Gerut.

Trevor Hoffman entered in the ninth to earn his 27th save of the season by striking out the side.

In the visitors' sixth, Chad Tracy singled with one out, moved to third on a single to left from Adam Dunn and scored on a Reynolds sacrifice fly. Baek exited in favor of Clay Hensley, who immediately gave up an RBI triple to Montero and an RBI double to Young. Johnson completed the scoring by lacing a run-scoring single to left.

The Pads made it a game with a three-run seventh. Gerut tripled to right- center with one away and scored on a Gonzalez infield single. Hundley followed with a two-run shot to left to make it a one-run game.

"The pitch to Hundley, it kind of came out of nowhere the way he was pitching," Arizona skipper Bob Melvin said of Johnson's performance. "He was cruising pretty well and all of a sudden it's a 4-3 ballgame and a completely different game after that."

Game Notes

Arizona swept a three-game series from the Padres last week and finished off the season series with a 10-8 edge, with four of those victories coming in San Diego...The Padres will play host to the Rockies for a three-game weekend set following an off-day Thursday while Arizona returns home for a decisive three- game series with the Dodgers following Thursday's off-day...The Padres optioned pitcher Josh Banks to Triple-A Portland and activated pitcher Bryan Corey from the 15- day disabled list and sent him to Portland prior to the game.