PITTSBURGH -- The Evan Gattis story just keeps getting better.

So do the Atlanta Braves.

The rookie catcher hit a pinch-hit two-run homer in the eighth to lift the Braves to a 6-4 victory over the Pittsburgh Pirates on Thursday.

Gattis turned on a sinker from Pittsburgh reliever Jared Hughes (1-1) and drilled it down the line to continue his remarkable emergence.

"I was a little surprised," Gattis said. "I didn't think I hit it hard enough. It started hooking and I'm glad it did because I don't think it would have gone out otherwise."

Maybe Gattis shouldn't be shocked. The former highly coveted high school player turned janitor and ski-lift operator (among other odd jobs) turned late bloomer is helping power the Braves to the league's best record.

"He's got a pretty cool story if you dig into it," Pittsburgh manager Clint Hurdle said. "Unfortunately I didn't dig the swing he put on it."

Atlanta brothers B.J. and Justin Upton homered in the same game for the second time this season as the Braves continued their torrid play.

Atlanta improved to a major league-best 13-2 after Gattis smacked a home run in his first pinch-hit appearance in the majors.

"I'd only ever pinch hit one time before and that was in rookie ball and I think I grounded out to short," Gattis said.

Anthony Varvaro (1-0) won in relief of starter Julio Teheran. Craig Kimbrel worked a perfect ninth for his seventh save.

Russell Martin and Pedro Alvarez each hit their first homer of the year, but the Pirates couldn't climb above .500. Travis Snider added two doubles and Garrett Jones drove in two runs.

The Uptons homered in the ninth inning of a 6-5 comeback win over the Cubs on April 6. This time, they didn't wait so long to get started.

B.J. Upton led off the game with a shot to left and Justin added a solo drive in the fifth for his ninth of the season, most in the majors.

Their power kept the Braves in it following another subpar start from Teheran.

Atlanta pitchers came in with a 1.77 ERA -- easily the best in baseball -- but Teheran continued to be the one member of the starting staff still searching for solid footing.

The 22-year-old struggled with his command in five innings, giving up four runs and seven hits while striking out four and walking three.

"He was OK," Atlanta manager Fredi Gonzalez said. "He got some balls out over the plate and he had people on base in every inning."

Teheran had been lights-out against right-handed batters but allowed Martin's first homer with the Pirates leading off the second. Alvarez -- in the midst of a 4 for 45 (.089) slump to begin the season -- drilled a 91 mph slider to the batter's eye leading off the fourth.

While Teheran is a permanent part of Atlanta's future, Pittsburgh left-hander Jeff Locke's job security is more tenuous. He won a starting spot almost by default after injuries to Jeff Karstens and Francisco Liriano gave the Pirates a major hole at the back end of the rotation.

Locke's first two starts were adequate and Hurdle said there is a "window" for Locke to convince the Pirates to keep him around even after Liriano and Karstens return.

The 25-year-old Locke struggled keeping the Uptons -- and their teammates -- in check, giving up four runs and six hits with four walks and three strikeouts in 4 2/3 innings.

Both starters left the game with a 4-all tie before the Braves broke through against Hughes.

Andrelton Simmons led off the eighth with a walk and moved to second on a sacrifice bunt before Gattis entered as a pinch-hitter. Pittsburgh pitching coach Ray Searage came out to chat with Hughes, but three pitches later Gattis turned a sinker that appeared to be ball three and drilled it down the line to put the Braves in front to stay.

"I just fell behind him," Hughes said. "The ball didn't sink and he did a good job of getting his hands inside of it and hitting it hard."

Atlanta is unbeaten when it scores. The Braves' only losses have come by shutout, including a 1-0 loss to Kansas City on Wednesday that ended a 10-game winning streak.

The Braves picked right back up at the start of a 10-game road trip, trading shots with the Pirates through five before breaking away late.

Game notes
Liriano will make a start for Double-A Altoona on Saturday. The left-hander is expected to throw four innings or 65 pitches. Liriano is recovering from a broken right arm and could be called up to Pittsburgh within the next two weeks. ... Atlanta will monitor the health of left-handed reliever Luis Avilan, who left Tuesday night's game against Kansas City with a severe cramp in his left hamstring. Avilan will be placed on the disabled list if the leg doesn't improve by Sunday. ... The series continues Friday when Tim Hudson (2-0, 2.50 ERA) faces Pittsburgh LHP Wandy Rodriguez (1-0, 1.00).