Ryan Ludwick's one-out solo homer in the 10th inning gave the Reds a 3-2 win over the St. Louis Cardinals in the second edition of a three-game set.
Sam LeCure (3-2) pitched a perfect top of the frame for the Reds, who have won five straight games.
Jay Bruce slammed a pair of doubles and knocked in a run for Cincinnati.
Victor Marte (2-2) replaced Marc Rzepczynski in the 10th, but served up the deciding blast to left field.
Yadier Molina clubbed a solo homer for the Cardinals, who have lost three of their last five.
After falling behind 0-2, Ludwick worked a full count. Then he hit a 3-2 slider on a line that just cleared the left-field fence.
"Slider, saw it and checked my swing that second pitch," Ludwick said. "I was kind of looking for it the rest of the at-bat."
Starting pitchers Kyle Lohse and Mike Leake were dealing early in the game before Cincinnati finally got to Lohse in the fifth. With two outs, Brandon Phillips singled and Bruce doubled to give the Reds the lead.
Cincinnati picked up a second run in the sixth after Scott Rolen and Devin Mesoraco started the inning with a pair of singles. After Leake moved the runners to second and third with a sacrifice bunt, Zack Cozart lofted a fly ball to right field to plate Rolen.
St. Louis came back to tie the game in the seventh. Molina led off with his 14th home run. David Freese followed with a single and Skip Schumaker chased Leake from the game with a double. Two batters later, Rafael Furcal bunted for a base hit off of Sean Marshall to tie the game.
Marshall and Logan Ondrusek escaped a jam later in the seventh, though, and the Cardinals stranded the bases loaded in the eighth, keeping the game tied.
"We had some opportunities," Cardinals manager Mike Matheny said. "We had our chances."
At least one home run has been hit in the last 67 games at Great American Ball Park...Cardinals outfielder Matt Holliday, who went 1-for-5, extended hit hitting streak to 13 games...St. Louis went 1-for-10 with runners in scoring position and stranded 11 on base...Cincinnati went 1-for-8 with RISP while also leaving 11 on base...Lohse received a no decision after six innings, giving up two runs on eight hits with three strikeouts. He has a 1.42 earned run average in three starts against the Reds this season (three earned runs in 19 innings)...In his last eight starts, Lohse has a 2.12 ERA (13 earned runs in 55 1/3 innings)...Leake went six-plus innings and gave up two runs on seven hits and a walk. He has a 1.95 ERA in his last five starts (eight earned runs in 37 innings) and a 2.59 ERA over his last 11 outings (21 earned runs in 73 innings), 10 of which have been quality starts.