SAN DIEGO -

Logan Forsythe and Alexi Amarista had key hits in a five-run fourth inning, and the San Diego Padres beat the St. Louis Cardinals 6-4 Tuesday night to send the slumping World Series champions to their 10th loss in 13 games.

St. Louis maintained a one-game lead over the Los Angeles Dodgers for the NL's second wild-card berth but dropped 10 1/2 games behind Cincinnati in the NL Central.

Forsythe, a homer shy of the cycle in Monday night's 11-3 win over St. Louis, doubled in two runs and Amarista added a two-run triple as San Diego erased a 2-0 deficit in the fourth.

Edinson Volquez (10-10) allowed three runs -- two earned -- and four hits in 5 1-3 innings, striking out six and walking six. He has a career-high 100 walks, the most in the majors this season.