Clint Hurdle decided to keeppitching on his regular day so he didn't miss the showdown with the .
Thehad a day off Thursday that allowed Burnett to face the Reds and improve to 7-2 after a team loss.
Burnett remained undefeated against the Reds this season and Starling Marte hit a tiebreaking two-run triple to help thesalvage the finale of their three-game series with a 6-2 win on Sunday.
''I've never had an ace before,'' Hurdle said. ''We have a guy with the experience A.J. brought with him.
hit a two-run home run and All-Star center fielder Andrew McCutchen added a solo shot as Pittsburgh snapped Cincinnati's win streak at five and cut the Reds lead in the National League Central Division to 4 1-2 games.
Burnett (14-3) allowed just one hit after the first inning and retired 18 straight batters before yielding two walks with two outs in the ninth. He allowed three hits and two runs with three walks and seven strikeouts in 8 2-3 innings to improve to 3-0 in three starts against the Reds this season.
''After the second inning he was just rock solid. He got some quick outs,'' Hurdle said.
Burnett shrugged off the stopper's tag.
''I just want to win whatever it takes, if it's my day it's my responsibility.''
Joel Hanrahan got the final out for his 32nd save.
A heavy rain began to fall in the top of the ninth and likely prevented Burnett from completing the game.
''It was nothing I haven't faced before,'' Burnett said. ''I probably should have called time but with three outs to go, I was trying to get through it real quick.''
The Reds went into the game with 22 wins in their last 25 games and 15 of their last 16. They are still 16-4 since All-Star first baseman Joey Votto left the lineup with a torn meniscus in his left knee that required surgery.
A pennant race is a new experience for most of the Pirates. Not Burnett.
''I've been in October. This is nothing like October,'' Burnett said.
Still the win prevented the Pirates from falling too far behind. The Reds badly wanted a sweep.
''You get greedy,'' Cincinnati manager Dusty Baker said. ''When you start winning every day, two out of three isn't good enough. We went 5-2 on the home stand, but you always want more. We're in a situation now where, hopefully, we get some guys back. Our guys have fought through some adversity.''
Jay Bruce doubled in the first, but Pittsburgh took a 2-1 lead in the second on Walker's 12th homer of the season, a two-run shot that tied Walker's season high.
After Stubbs tied the score with his 14th homer of the season, the Pirates went back ahead on Marte's two-run triple that followed singles by Gaby Sanchez and Clint Barmes.
Homer Bailey (9-7) allowed nine hits and four runs with one walk and three strikeouts in 4 2-3 innings on Sunday.
''Homer wasn't real sharp,'' Baker said. ''Burnett was real sharp. He got into trouble early, but he got out of it and sailed along until the ninth. He's tough. He's rediscovered himself. He's not 14-3 for nothing.''
McCutchen led off the ninth against Logan Ondrusek by tying his single-season career high with his 23rd homer of the season and first since July 17.
''Considering it's been a while and I haven't been feeling that great, it felt good,'' McCutchen said.
NOTES: Reds 2B Brandon Phillips missed his fifth straight start with a strained left calf. ... The Pirates finished 6-4 on their longest road trip of the season. They open their longest homestand Monday with a four games against Arizona, the first of 11 in 11 days in Pittsburgh. ... The Reds open a seven-game road trip in Milwaukee on Monday. They've won nine consecutive road games, the longest active streak in the National League and the team's longest since a 10-game run from July 27 through Aug. 13, 2005.