Burnett (6-8) held the Padres to four hits and a walk over seven innings and extended the the Pirates' lead over St. Louis in NL Central to two games.
Burnett had plenty of offensive support in the win. Josh Harrison drove in three runs and Andrew McCutcheon had two RBI. The Pirates, who had three triples in the game, scored five runs in the seventh inning to put the game on ice.
Jedd Gyorko accounted for the lone San Diego run with a fourth-inning homer. Tyson Ross (3-6) allowed five runs -- four earned -- on six hits over 6 1/3 innings. The Padres lost for the 10th time in 14 games.