Atlanta (42-52) is on pace for its worst finish since it went 65-97 in 1990, the season during which current manager Bobby Cox took over the club in June.

The Braves would be in much better position if they hadn't lost all 19 of their one-run games on the road. Overall, they've dropped 26 straight road games decided by one run since edging the New York Mets 7-6 on Aug. 9 of last season.

That skid continued on Wednesday, when the Braves managed five hits in a 3-2 loss to San Francisco. The Braves, whose 19-37 road record makes them one of three teams in the majors with fewer than 20 victories away from home, have scored two or fewer runs in 22 of their 56 road games - all losses.

"You've got to score," said Cox, whose team has lost nine of 12 overall. "It's hard to score in this ballpark and not only that, it's hard to score with their pitchers, so you've got to take advantage of everything you can get."

Arizona's Chase Field is generally considered a more hitter-friendly ballpark than San Francisco's AT&T Park, and that's helped the Diamondbacks (59-55) average 5.1 runs while going 32-23 at home.

However, the stadium didn't help Arizona much on Wednesday, when Pittsburgh's Jeff Karstens had a perfect game through 7 2-3 innings and limited the Diamondbacks to two total hits in the 2-0 loss - their first time to get shut out at home since a 9-0 loss to Milwaukee on Aug. 20, 2007.

"It's just the way the day worked out," Diamondbacks outfielder Conor Jackson said. "I thought a bunch of guys had some good swings and hit the ball hard. You can't ask for much more than that, they just didn't fall today."

Despite the defeat, the Diamondbacks maintained their 2 1/2-game lead over the Los Angeles Dodgers in the NL West. They'll try to add to that lead on Thursday when they match up against Atlanta starter Charlie Morton (2-5, 6.56 ERA).

The right-handed rookie lost his third straight start Saturday despite holding Milwaukee to two runs and four hits in a season-high seven innings of the 4-2 defeat. He retired 15 straight batters before yielding the go-ahead runs in the seventh.

"It was a confidence builder, a big step," Morton said. "I just hope I can build on it. My first five outings, it was hard to realize I was pitching in the big leagues. Today it was more of a feeling that it was just a baseball game. It was the first time I felt like that."

The Diamondbacks will counter with Yusmeiro Petit (1-2, 3.03), who gave up three runs in five innings of a 4-2 loss to the Dodgers on Saturday. The right-hander is 0-1 with an 8.03 ERA in three career games - two starts - against the Braves.