WASHINGTON -- Jose Vidro picked a good time to start getting clutch hits.
"I've missed a lot of chances to contribute to the ballclub," Vidro said. "This has been the biggest hit of the year for me right now."
Vidro had gone 1-for-13 with runners in scoring position before a run-scoring single in the sixth -- his first RBI since July 14. Hitting just 5-for-35 (.149) in his previous 10 games, he sat some while Washington used Bernie Castro, Marlon Anderson and Damian Jackson at second.
"It's good to see anybody come through," Washington manager Frank Robinson said. "He's been struggling."
Vidro notched the winning hit off Jason Isringhausen (4-8), who has blown 10 saves in 43 saves.
Isringhausen threw 28 pitches in saving Tuesday's 2-0 win but told manager Tony LaRussa that he could pitch Wednesday.
Felipe Lopez walked to start the inning, Nick Johnson was hit by a pitch with one out and Ryan Church walked after falling behind 0-2 in the count. Vidro then lined a single past first baseman Albert Pujols and down the right-field line on a 1-0 pitch.
"I just couldn't find the strike zone," Isringhausen said. "Once I started missing, I was trying to do too much, trying to overcome it. Then I had throw a pitch right down the middle to get a strike."
Washington led 5-4 before Preston Wilson's two-run, upper-deck homer in the top of the ninth off Chad Cordero (7-4), who blew a save for the fourth time in 28 chances -- but first since the All-Star break.
Johnson had an RBI single in the first, but Scott Spiezio's three-run homer gave St. Louis a 3-1 lead in the sixth. Washington then scored four runs in the bottom half when Vidro and pinch-hitter Brian Schneider hit RBI singles and Alfonso Soriano chased Chris Carpenter with a two-run single.
Yadier Molina cut Washington's lead to 5-4 with a solo homer off Jon Rauch in the seventh.
Nationals shortstop Lopez made a spectacular bases-loaded catch of a Ronnie Belliard's bloop in the eighth.
- The Nationals said second-round draft pick Sean Black attended classes at Seton Hall, ending the team's eligibility to sign him.
- Spiezio's homer was his first since Aug. 10 against Cincinnati.