(Reuters) - Scott Rolen rediscovered his touch with a game-winning, two-run single that gave the Cincinnati Reds a sixth successive victory with a 4-2 triumph over the St Louis Cardinals on Sunday.

Ryan Ludwick, who had blasted a walk-off home run for the Reds in the 10th inning a day earlier, was intentionally walked in the eighth inning to load the bases and set the stage for Rolen's two-out hit.

The 37-year-old is batting just .197 in an injury-blighted season but was able to have the final say in a game in which he batted 2-for-4.

"I've been trying to put decent at-bats together all year but haven't had much success," Rolen told reporters.

"Hopefully I can put some good swings on it and good things will happen."

The win gave Cincinnati (50-38) a one-game lead over the Pittsburgh Pirates in the National League Central and completed a three-game sweep of divisional rivals St Louis (46-43), who are now four-and-a-half games behind.

Homer Bailey (8-6) tossed eight innings in the victory, escaping a jam in the eighth when two Cardinals runners reached base with no outs, before Aroldis Chapman blew the visitors away with three strikeouts in the ninth for his 13th save.

"This was a big game, a huge game," Cincinnati manager Dusty Baker said. "“We were trying to stay away from (using) Chapman, but in a situation like that, that's his game."

The Reds scored twice in the third inning to take a 2-1 lead but Yadier Molina tied the game with a solo blast in the sixth. Molina finished 3-for-4 with two RBIs.

Jake Westbrook (7-8) tossed 7 1/3 innings and took the loss for the Cardinals.

(Writing by Jahmal Corner in Los Angeles; Editing by John O'Brien)