WASHINGTON — Salomon Torres lost command of his split-finger fastball at an inopportune time.

Cristian Guzman scored the game-winning run on a ninth-inning wild pitch by Torres and the Nationals ended a three-game losing streak with a 6-5 victory over the Pittsburgh Pirates on Wednesday night.

"I could have been out of the inning. ... It didn't go my way," Torres said. "I kept aggressive. I kept the ball down. There's nothing I could have done differently. Unfortunately, that split-finger fastball got a little bit of sink towards our dugout — and you know what happened."

Torres (0-3), who was replaced as the Pirates closer by Matt Capps after blowing his fifth save Sunday, had problems with the splitter from the start. Though he struck out Felipe Lopez on a 3-2 pitch to open the ninth, two of Torres' first four pitches to Lopez — both split-finger offerings — bounced a foot in front of the plate for balls.

Guzman started the decisive rally with a one-out single and Ryan Zimmerman hit a broken-bat infield single to third. One out later, Austin Kearns walked to load the bases before Torres bounced a 1-1 pitch at Ryan Church's right foot, with the ball scooting away.

"He threw a lot of split and all the splits he threw, he threw in the dirt," said Guzman. "I told the third-base coach, 'Watch his hand, if he throws it again, I'm going to go home.' "

Torres took full responsibility for the pitch selection.

"I could have gone with a fastball. I could have gone with a curveball. I had five different options. I chose to go with the split," he said.

Chad Cordero (1-0) pitched a perfect ninth for the victory after the bullpen squandered a 5-1 lead in the eighth.

Dmitri Young had three hits and Brian Schneider two RBI for Washington, which is 3-5 on a nine-game homestand that concludes Thursday.

Trailing 5-2, Adam LaRoche hit a three-run homer in the eighth for the Pirates to tie the game.

"We did a great job to get back into the game. Unfortunately, the bottom of the ninth inning didn't work out so well for us. ... The ninth inning, they scored a run (and) the ball didn't leave the infield," Pirates manager Jim Tracy said.

Kearns' two-out RBI double put Washington up 1-0 in the first. The Pirates responded with a run-scoring double by Ryan Doumit in the second.

The Nationals retook the lead in the second. Schneider and Nook Logan singled, both advanced on Micah Bowie's sacrifice and Schneider scored on Felipe Lopez's groundout.

Washington added to the lead in the fifth, using an error by shortstop Jack Wilson on a potential inning-ending double play to extend the rally.

With one out, the Nationals loaded the bases on a walk to Zimmerman, Young's single and a walk to Kearns. Ryan Church hit a bouncer to Wilson, who bobbled the grounder, and Zimmerman scored on what was ruled a fielder's choice and an error.

On the next pitch, Schneider singled sharply to center for a 5-1 lead.

The Pirates tied the game in the eighth. Jose Bautista walked and moved to second on Jon Rauch's wild pitch. Freddy Sanchez's single moved Bautista to third and he scored on Jason Bay's sacrifice fly. Ronny Paulino singled, Billy Traber relieved Rauch and LaRoche hit a 2-1 pitch over the wall in center for his seventh homer.

Bidding for his third straight win, Bowie allowed a run and two hits in five innings. He walked five and struck out five.

Pittsburgh left-hander Zach Duke, who has one victory in his last 11 starts, gave up five runs and nine hits.