It's difficult to imagine Bud Norris pitching any better than he did in his last two starts. He could have used some run support from his Houston Astros teammates, though.

After a scoreless duel between Norris and Los Angeles Dodgers counterpart Hiroki Kuroda, Dioner Navarro homered off reliever Wilton Lopez in the eighth inning Sunday and the Astros lost their second straight 1-0 decision with Norris on the mound.

Navarro's one-out single in the second was the only hit Los Angeles got off Norris in his six innings of work. The right-hander threw 99 pitches and struck out five before he was lifted for a pinch-hitter with the potential go-ahead run at second base. But Kuroda retired Matt Downs on a popup, stranding Chris Johnson and leaving Norris with a frustrating no-decision.

"I felt strong. I feel like I'm a guy who can go deep into ballgames and throw 120 pitches. Unfortunately I got pulled right there, and I'm not very happy about it," Norris said.

"I know these guys are playing hard, and they're close ballgames. I didn't really get an opportunity to stay out there and last longer for these guys, because I know they're trying hard and maybe they could have scratched one out. But it just didn't work out that way. I'm pretty frustrated. I just go out there and do my job. That's all I can manage."

Navarro drove a 2-0 pitch from Lopez (1-3) into the pavilion seats in right-center. Matt Guerrier (3-3) pitched a perfect inning for the win and Javy Guerra got three outs for his second save.

Norris wanted this win so badly, he bolted off the mound in the sixth inning on a bunt by Kuroda in foul territory and went face-first into the grass as the ball landed 2 feet out of his reach. Neither first baseman Brett Wallace nor catcher Carlos Corporan thought they had a play on it.

"I gave it my best effort. It wasn't very pretty, but I gave it my best effort," Norris said. "I'm a bulldog, and I'm going to leave my effort on the field."

Kuroda allowed three hits over seven innings and struck out six. The right-hander was 0-5 with a 4.39 ERA in his previous five starts, following consecutive scoreless outings of at least seven innings each against Pittsburgh and Milwaukee — both of which the Dodgers eventually won by shutout.

With right fielder Hunter Pence back in Houston getting an MRI on his hyperextended left elbow, Astros manager Brad Mills was forced to replace Gold Glove center fielder and leadoff hitter Michael Bourn after he was ejected by umpire Jeff Nelson for arguing a called third strike that ended the fifth inning.

"I let him know it was in," Bourn said. "I was just asking, where was it? I didn't cuss at him, didn't do any of that. He said I can't talk about a call. Why not? I thought that's what we do. I just didn't understand, and then he threw me out of the game. I don't argue too many calls."

Bourn was suspended for one game last season for making unintentional contact with umpire Alfonso Marquez after getting called out at first base on a close play in the ninth inning of a 2-1 loss to San Diego.

"I always regret getting tossed, but I was in the moment," Bourn said. "Why did I get tossed? That's what I wanted to know afterward."

Mills received his third ejection of the season after coming out to confront Nelson in the middle of the sixth.

"I thought they were both unnecessary, but that's not my call," Mills said. "I was pretty frustrated with them complaining to us talking about balls and strikes — and then they threw Michael out. We thought that ball was inside, and I went out just to talk to him about it. He threw me out, and that's when I got a little bit heated."

The Astros had two runners in scoring position in the second and third, both times after wild pitches by Kuroda. But the 36-year-old right-hander escaped the first jam by slipping a called third strike past Corporan, then retired Carlos Lee on a popup to end the third.

"We were trying to get (Norris) some runs," Johnson said. "When he pitches, we know if we just scratch a couple across we'll probably be pretty good because he's got really good stuff and is feeling really well right now."

The Dodgers got a runner as far as second base in consecutive innings, but Norris came away unscathed in the third by striking out rookie Dee Gordon on a changeup and in the fourth by fanning James Loney on a slider down and in.

"Big starters have got to bear down and leave that guy there," Norris said. "You don't (want to) give them a real opportunity to drive that guy in, and that's exactly what I did."

NOTES: Johnson, who began the series 1 for 18 lifetime against Dodgers pitching, had six hits in 13 at-bats this time around — including four doubles. ... Dodgers C Rod Barajas was placed on the 15-day disabled list with a sprained right ankle.