PHOENIX -- Brandon Webb set a personal best with his latest win and is now just one victory from being the National League's first 20-game winner in three years.

The right-hander pitched seven shutout innings for his career-high and major league-leading 19th victory Thursday night in Arizona's 4-1 win over San Diego.

The Diamondbacks won for the eighth time in 10 games and maintained their two-game lead over the Los Angeles Dodgers in the AL West.

"It was a good win," said Webb (19-4), the NL's Cy Young winner in 2006. "Pretty much from here on out it's just so close. We're trying to win every game for the team. If I clean up on decisions, great, but I'm just trying to go out and get deep into the game, give us a chance to win."

Boston's Josh Beckett won 20 games last season, but the NL hasn't had a 20-game winner since Chris Carpenter of St. Louis, Roy Oswalt of Houston and Dontrelle Willis of Florida in 2005.

Webb, who hasn't lost since a 5-3 decision at Minnesota on June 22, walked three. It was the sixth straight winning start for Webb and he has eight wins in his last 11 starts. He allowed three hits with eight strikeouts, both tying season bests.

"I've got a lot of confidence, especially with the guys hitting out there and playing defense behind me the way they are," said Webb, who won 18 games last season. "I've been able to get down in the zone, low, and get a lot of ground balls and strikeouts."

The D-backs open a three-game series tonight at Chase Field against the Florida Marlins.

(Copyright 2008 by The Associated Press. All Rights Reserved.)