It was Burnett's 160th career win, fifth most among active players. The 38-year-old has said this will be his last season.
Burnett allowed five runs -- four of them earned -- the same numbers, precisely, as his last six starts combined.
"He's had a great start to the season. I think this was his 10th start," Pirates manager Clint Hurdle said about his right-hander, back for the second time with the club. "We complicated things in the fourth and the fifth [defensively] or there's no telling what the line would have ended up. It was what is was.