Updated

WASHINGTON -- Stephen Strasburg won his 12th consecutive decision dating to last season and Jayson Werth connected for a pinch-hit grand slam to help the Washington Nationals close out the season series against the St. Louis Cardinals with a 10-2 win on Sunday.

Wilson Ramos had three hits, including a two-run homer, and drove in four runs. Bryce Harper hit an RBI single during Washington's three-run fourth inning off Michael Wacha (2-6).

Strasburg (9-0) pitched six innings of one-run ball as Washington salvaged a split of the four-game series. The Nationals went 5-2 against the Cardinals this season.

Strasburg improved to 12-0 in 15 starts since losing to the Mets on Sept. 9, and the Nationals have won all 15 of those games. The 12 consecutive winning decisions is a franchise record for a starter, breaking a mark shared by Livan Hernandez (2005) and Dennis Martinez (1989).

The right-hander also became the first starter in franchise history to win his first nine decisions in a season, one more than Pedro Martinez in 1997. Washington is 11-0 this season in games started by Strasburg, who lowered his ERA to 2.69 and tied Chicago Cubs ace Jake Arrieta for the NL lead in wins.

Anthony Rendon and Werth homered in the seventh for Washington in its final game before a three-city road trip.

Brandon Moss hit a solo home run off Strasburg for a short-lived lead. Matt Holliday had three hits for the Cardinals.

Werth's drive off Dean Kiekhefer highlighted the decisive five-run seventh as Washington batted around. Rendon started the inning with a homer after St. Louis made it 3-2 in the top of the inning on Matt Adams' sacrifice fly.

Wacha dropped his sixth straight decision after starting the season 2-0. He was unable to complete more than four innings in any of his three previous starts while allowing 20 earned runs combined.

Though he worked deeper against the Nationals, the fourth inning was costly.

The Nationals went 1 for 13 and no RBIs with runners in scoring position over the first three games. That futility ended in the fourth. Following Michael Taylor's leadoff double, Harper's single tied it at 1.

Ryan Zimmerman's one-out double put runners on second and third. After Rendon struck out, Ramos drove in both runners with a two-out single.

TRAINER'S ROOM

Cardinals: Adams went 0 for 2 with a walk in his first start since exiting Thursday's game with mid-back stiffness. He had a two-run, pinch-hit double in Saturday's 9-4 win.

Nationals: RHP Matt Belisle (right calf strain) allowed two runs over two innings Saturday in his third rehab appearance with Single-A Potomac. Belisle visited Washington's clubhouse Sunday and said he expects to pitch for Double-A Harrisburg on Tuesday before Washington decides on his next step.

UP NEXT

Cardinals: RHP Carlos Martinez (4-5, 4.25 ERA) looks to snap a string of five consecutive losing decisions as St. Louis opens a three-game series at Milwaukee. RHP Junior Guerra (3-0, 3.30 ERA) starts for the Brewers.

Nationals: Washington's nine-game road trip opens Monday in Philadelphia. The Nationals' Tanner Roark (3-4, 2.71 ERA) will face fellow RHP Jeremy Hellickson (4-3, 3.97 ERA).