St. Louis (AP) -- And the Washington Nationals wait.

Already assured of the capital's first postseason baseball since 1933, the Nationals remained stalled in their drive for the NL East title when they lost to the St. Louis Cardinals 10-4 Sunday.

"We've got to play the type of baseball that we're capable of playing," infielder Ian Desmond said. "We didn't do that today."

Carlos Beltran homered from both sides of the plate to lead the Cardinals.

Washington (96-63) saw its magic number for clinching the division remain at one with three games remaining. The Nationals return home to face Philadelphia starting Monday, while Atlanta plays at Pittsburgh.

Washington, 16-12 in September, is seeking the franchise's first division crown since the Montreal Expos won the East in 1981

"We've played all year to get to this point," Jayson Werth said. "Now we've got one game to win, and we get to do it at home."

St. Louis (86-73) took a 7-0 lead by the third inning and in the race for the NL's second wild-card berth holds a two-game lead over the Los Angeles Dodgers (84-75), who beat Colorado 7-1.

"We're one step closer, but there's still a long way to go," Cardinals manager Mike Matheny said. "We've got to keep playing and playing well. The guys came out pushing today against a very good team."

Lance Lynn (18-7) allowed four runs and six hits in 5 1-3 innings, improving to 5-0 with a 2.10 ERA in his last five appearances.

Beltran hit a pair of two-run homers, connecting right-handed off Ross Detwiler (10-8) in the second and left-handed against Chien-Ming Wang in the fourth. Beltran has four multihomer games this season and 34 overall, and homered from both sides for the ninth time in his career. He improved to 32 homers with 97 RBIs in his first season with St. Louis.

Pete Kozma was 3 for 3 with three RBIs, raising his average to .338.

Rookie Bryce Harper hit his 22nd home run for Washington, a solo shot. Danny Espinosa also had a two-run homer for the Nationals.

"We've had rough outings before," Nationals manager Davey Johnson said. "We've bounced back. It's better to clinch it at home, anyway"

Detwiler (10-8), a St. Louis area native making his first start in his hometown, allowed seven runs - three earned - four hits and five walks in 2 1-3 innings. He set season highs for fewest innings and most walks.

"I just didn't throw any strikes," Detwiler said. "You walk five people in two innings, you won't have much success doing that."

St. Louis took a 5-0 lead in the second after Yadier Molina and David Freese walked, and second baseman Danny Espinosa booted Daniel Descalso's grounder, loading the bases. Kozma hit a two-run double down the right-field line, with Descalso thrown out at the plate on Espinosa's relay from Jayson Werth. Jon Jay's one-out single made it 3-0, and Beltran homered.

Harper's homer, Ian Desmond's RBI double and Espinosa's two-run homer cut the deficit to 7-4 in the fourth, but Beltran connected off Wang in the bottom half, and Beltran hit an RBI single against Zach Duke.