Webb scattered six hits in eight innings to win his big league-leading 15th game, and the Diamondbacks beat Los Angeles 2-1 Thursday night to extend their NL West lead over the Dodgers to two games.
Webb (15-4) walked one and struck out six in outpitching Derek Lowe and continuing his domination of the Dodgers. The 2006 NL Cy Young Award winner is 8-0 in his last nine starts against Los Angeles, allowing nine runs in 71 innings.
"I've had some good luck against those guys," said the 29-year-old right-hander, who has a 10-3 lifetime record against the Dodgers and hasn't lost to them since July 7, 2004. "That was probably some of the best stuff I've had all year. I was able to keep the ball down.
"In my eyes, it's the biggest one we've had all year."
Brandon Lyon blanked the Dodgers in the ninth to earn his 23rd save in 28 chances.
The win was the sixth in seven games for the Diamondbacks while the Dodgers lost for just the second time in seven games.
Slugging outfielder Manny Ramirez, acquired by the Dodgers from Boston earlier Thursday, is expected to make his Los Angeles debut Friday night against Arizona's Randy Johnson in the second game of a four-game series.
"I don't know exactly how it all worked out, but I'm happy it did," said Lowe, who played with Ramirez in Boston from 2001-04. "He's going to bring another element to our offense. It's going to be a great addition. I think everyone's looking forward to getting him out there tomorrow and letting him do his thing."
The Dodgers took a 1-0 lead in the sixth when Juan Pierre hit a one-out single, took third on Matt Kemp's hit-and-run single and scored when second baseman Orlando Hudson trapped Russell Martin's broken-bat blooper and threw him out at first. Kemp's hit extended his hitting streak to a career-high 18 games.
The lead didn't last long. Conor Jackson doubled to open the Arizona seventh, took third on Chad Tracy's infield out and scored on a double by Mark Reynolds, snapping the Dodgers' scoreless inning streak at 29 innings -- their longest such streak since they held the opposition without a run for 38 innings in 1991. Chris Snyder followed with a single to drive in the go-ahead run and chase Lowe (8-9).
"You're not allowed much leeway when you pitch against a guy like Webb," Lowe said. "You really have to pitch near-perfect baseball to beat him. That's always a good challenge, but you know you've got to put up zeros. The most frustrating thing was getting a one-run lead and giving it back on 10 pitches."
The Dodgers threatened in the eighth when pinch hitters Andre Ethier and Mark Sweeney singled to open the inning and Pierre sacrificed. Kemp followed with a liner to left, which Jackson raced in to catch before making a one-hop throw to nail Ethier at the plate. Snyder made a lunging tag, ending the inning.
"He got it there, that was his job," Snyder said. "The rest was my part. That's the game right there."
Jackson, a converted first baseman, said he believes teams are going to be aggressive against him because of his inexperience in the outfield.
"It wasn't a perfect throw," Jackson said. "[Snyder] made an unbelievable play. Hats off to him."
Lowe, who gave up one hit in eight shutout innings against Washington in his previous start, allowed seven hits and two runs in 6 1/3 innings with no walks and seven strikeouts.
Alex Romero and Stephen Drew singled in the Arizona third, but third baseman Casey Blake turned Chris Young's broken-bat liner into an inning-ending double play. The Diamondbacks wouldn't get another baserunner until Drew hit a ground-rule double with one out in the sixth for his third hit. Young struck out and Hudson hit a comebacker to end the inning.
Pierre singled to start the fourth for the first Los Angeles hit, but Kemp grounded into a double play. Martin followed with a single and James Loney walked before Blake struck out.
Dodgers second baseman Jeff Kent didn't play because of a jammed knee. He was injured while sliding into third base Wednesday night against the Giants and is listed as day-to-day.
Before the game, the Dodgers and Diamondbacks had both won or lost on the same day for eight straight games beginning July 23. ... Los Angeles pitchers have gone eight games without giving up a home run -- the team's longest such streak since a nine-game stretch early in the 1996 season. The Dodgers have given up a big league-low 78 homers. ... Arizona manager Bob Melvin used the same batting order (Nos. 1-8) for the second straight game. He has used 93 different lineups through 108 games. ... The Dodgers finished July with a 16-10 record after going 11-16 in June. ... The Diamondbacks have a 28-13 record against NL West foes and a 28-39 mark otherwise. They won the division last year by going 36-36 against NL West opponents and 54-36 otherwise.