WASHINGTON -- Second baseman Kolten Wong had three hits, including a tiebreaking double in the eighth inning, as the St. Louis Cardinals beat the Washington Nationals 7-5 Wednesday to even the three-game series between the defending division champions.

Wong, who also had a two-run homer in the second, drilled a double down the left field line with one out in the eighth against reliever Blake Treinen (0-2) to make it 6-5. The hit scored center fielder Jon Jay, who walked and went to third on a single by catcher Yadier Molina (two hits).

St. Louis first baseman Matt Adams (two hits) drilled a solo homer in the ninth against Rafael Martin to give the Cardinals an insurance run.

The winning pitcher was Kevin Siegrist (1-0), who did not allow a run in 1 1/3 innings. Trevor Rosenthal pitched a perfect ninth for his fifth save.

St. Louis (9-4) won for the sixth time in seven games while the Nationals (7-8) lost for just the second time in six games. The Cardinals won for the 15th time in their past 22 games against the Nationals.

Washington starter Doug Fister gave up seven hits and five runs (four earned) in six innings. Fister was replaced in the seventh by Matt Grace, a UCLA product who made his big league debut by retiring three of four batters in his lone inning.

John Lackey went 5 1/3 innings and gave up eight hits and five runs, the worst outing by a Cardinals starter this year. Washington first baseman Ryan Zimmerman had two infield hits.

The Nationals scored five runs in the third inning to tie the score at 5 against Lackey, who had not allowed a run in his previous 12 innings.

Washington left fielder Jayson Werth had an RBI sacrifice fly, Zimmerman singled home a run, and third baseman Yunel Escobar drove in three runs with a two-out double with the bases loaded.

The Cardinals had taken a 5-0 lead in the top of the third after Adams had an RBI double and then scored when Zimmerman misplayed a grounder off the bat of Jay.

Wong hit a two-run homer with two outs in the third to give the Cardinals a 3-0 lead. Molina singled before Wong's blast.

Cardinals third baseman Matt Carpenter led off the game with a home run to right on a 2-2 pitch up in the zone from Fister. It was the sixth career leadoff homer by Carpenter, his second leadoff blast in four days and third overall this season. He was selected the National League Player of the Week on Monday and entered Wednesday, and he is hitting .377 this season.

Lackey collected the 1,800th strikeout of his career when he fanned shortstop Ian Desmond for the first out in the first inning. It was just the third time he faced the Montreal/Washington franchise, the last coming against the Nationals on June 23, 2008, when he pitched for the Los Angeles Angels.

Washington had not scored more than three runs in a game against the Cardinals in the previous eight meetings.

NOTES: The Nationals traded LHP Xavier Cedeno to the Los Angeles Dodgers for cash considerations. ... The Nationals called up LHP Matt Grace from Triple-A Syracuse and placed LHP Felipe Rivero on the 15-day disabled list, retroactive to April 18. ... The scheduled starters for the series finale Thursday are Washington RHP Max Scherzer (1-0, 0.83 ERA) and St. Louis RHP Michael Wacha (2-0, 1.35). Scherzer, a St. Louis native, last faced his hometown team in 2009 when he pitched for the Arizona Diamondbacks. ... Washington INF Yunel Escobar, whose walk-off homer beat St. Louis 2-1 on Tuesday, hit his previous walk-off homer in 2010. ... St. Louis OF Matt Holliday entered Wednesday with a hit in his first 12 games this season, but he went 0-for-4. ... Washington INF Anthony Rendon, who went on the disabled list April 5 with a left knee sprain, is slated to begin a rehab assignment Friday with Double-A Harrisburg, Nationals manager Matt Williams said.