LOS ANGELES -- Of all the adjectives used to describe pitcher Chad Billingsley, the one the Dodgers never expected heading into this season was ... winless.

The contradiction that is the right-hander was on display on Thursday night. He struck out a career-high 12, but was on the wrong end of a 6-4 Dodgers loss to the Diamondbacks.

"I could have done better. You're never happy with a loss," said Billingsley, who has four of them already after going 12-5 last year. "They found ways to score runs and capitalized on our mistakes."

Billingsley remains frustrated and frustrating. He has the talent of a first-round Draft pick and shows flashes of brilliance (32 strikeouts in 20 2/3 innings), but in the same game, fights his mechanics, loses his rhythm and basically undermines himself.

Again the Dodgers squandered a chance to build some momentum and slipped seven games back in the NL West. Coming off an upbeat 8-3 win on Wednesday night, they had a chance to sweep the two-game series and jumpstart their confidence level.

Instead, they again didn't do enough right to overcome the few things they did wrong. Those included hitting into a pair of double-play groundouts, plus a misplay by right fielder Matt Kemp of Miguel Montero's catchable line drive into a second-inning double. Billingsley followed by throwing a cut fastball into the home run swing of No. 8 hitter Jeff Salazar.

Also damaging was a disputed play by veteran second baseman Jeff Kent that led to an unearned Arizona run and, ultimately, the ejection of both Kent and manager Joe Torre in the ninth inning.

Kent's RBI bloop single in the bottom of the seventh inning cut Arizona's lead to 5-4. With one out and one on in the top of the eighth, Kent took third baseman Nomar Garciaparra's throw as he was stepping off the bag toward left field, content with a forceout of Conor Jackson on Mark Reynolds' grounder and no throw to first.

The way second-base umpire Andy Fletcher saw it, however, Kent came off the bag before he caught the throw, as if the throw pulled him off the bag. Fletcher called Jackson safe, he advanced on Scott Proctor's wild pitch and scored on Justin Upton's sacrifice fly.

Kent immediately argued the call with Fletcher, clearly saying he "blew the call." When Kent returned to the field for the top of the ninth, he revived the argument. Fletcher ejected Kent, who then took up the fight with crew chief Mike Reilly while Torre confronted Fletcher, who tossed Torre.

"It was a bad call. You saw the play," said Kent. "I challenged the call and got thrown out. I wasn't challenged back, I just got thrown out. It's a tough situation in the game, you're playing the game hard and you expect umpires to do the same. It's just a shame."

The replay was inconclusive, which backed up Torre's position.

"The only thing I stressed to Fletcher was that [Kent] didn't have to come off the bag to catch the ball," said Torre. "Unless it's clear-cut, you can't make that call. Unless it's really blatant, I didn't think it was necessary."

Fletcher said: "That's his opinion."

Fletcher also said he did give Kent an explanation why he made the safe call and added that he ejected Kent, "for something he said."

Kent at one point appeared nose-to-nose with Reilly, pointing his index finger at Reilly's chest, but the veteran umpire said whatever contact there might have been was incidental "in the heat of battle" and there was no indication that further disciplinary action would be recommended.

But, Reilly said the ejection was appropriate.

"You can't continue the argument the next inning," he said. "He had a chance to argue, then he came out again the next inning. You can't allow it to continue over one call."

As unwarranted as the Dodgers felt that run was, they had "plenty of opportunities with the right guys at plate and couldn't deliver," according to Torre. The numbers 3-4-5 in the order -- Garciaparra, Kent and James Loney -- went 6-for-11.

In the first inning, third-base coach Larry Bowa aggressively sent Garciaparra home from first on Kent's double, but Kent was stranded when Loney grounded out. The Dodgers left two on in the fourth when Billingsley grounded out. They had the bases loaded with one out in the sixth, but Kemp struck out and pinch-hitter Mark Sweeney flied out. And after Kent's seventh-inning RBI single, they had runners on the corners when Loney bounced into a double play.