Unfotunately for the Reds, they couldn't hold that lead, they lost a fifth straight series to St. Louis and they'll fly to Chicago a season-high four games out of first place -- this after an 11-4, 10-inning loss at Great American Ball Park on Sunday night.
"It's disappointing," Reds manager Dusty Baker said. "How can you not be disappointed? That was a game we had the lead going into the late innings. We've got to find a way to hold that."
The Reds' bullpen gave up nine runs in four innings -- including seven in the decisive 10th inning. Matt Holliday's grand slam off Curtis Partch, who was making his Major League debut, effectively put the game out of reach.
"That's not a situation where we'd like to bring Partch into his first game," Baker said. "That was just a bad series of events. That hurts right there, getting beat up like that."
"I knew he threw hard," Holliday said. "We had a little scouting report from [hitting coach John] Mabry as I was walking up there. I knew his fastball was 94-97. That's all I knew."
Six of the seven runs were charged to J.J. Hoover, who allowed three runners to score before exiting with the bases loaded.
The bullpen's meltdown spoiled a strong start from Bronson Arroyo.
Arroyo allowed just one hit through three innings before giving up three in the fourth, including a home run to Carlos Beltran and an RBI double to Yadier Molina that tied the game at 2.
Daniel Descalso grounded out to Arroyo to end the inning, but the ball bounced off his knee. The 36-year-old made the throw to first and quickly hobbled down the dugout steps and into the Reds clubhouse, emerging only when he was needed in the on-deck circle.
Arroyo returned to the mound in the fifth and pitched a scoreless frame -- in part because left fielder Derrick Robinson made a leaping, two-out catch near the wall to rob Beltran of extra bases. Arroyo followed with a scoreless sixth before exiting.
"It's not serious," Arroyo said. "It just got me in a good spot. There was no flesh, just a lot of bone. Fifth inning, I didn't really feel it, but going back for the sixth, I was having a hard time really putting weight on it.
"Once I made it through the sixth, I felt strong. My pitch count  was low enough to go back out one more time, but I just felt it'd be better for the ball club if somebody had been out there fresh instead of me putting a couple of guys on and then having to clean up that inning."
Arroyo allowed two runs on six hits and finished with four strikeouts and one walk.
The Reds got off to a fast start but were ineffective for much of the night.
St. Louis starter Lance Lynn had allowed just two runs in two starts against the Reds this year. On Sunday, he allowed two runs in the first inning -- one on an RBI bloop to shallow right by Brandon Phillips, and another on a sacrifice fly by Jay Bruce that scored Joey Votto.
Bruce struck again in the fifth, roping a two-out, two-run double down the right-field line to give the Reds a 4-2 lead.
The Reds, however, wouldn't score again, as their 6-9 hitters went a combined 0-for-14.
"We had some chances to tack on some runs," Baker said. "We've just got to score some more, especially late."
Cincinnati has been outscored 44-16 in its last eight games against St. Louis.
Lynn pitched six innings, allowing four runs on five hits to go with three walks and six strikeouts.
The Cardinals tied the game in the seventh with two runs off Sam LeCure, who yielded an RBI single to Matt Carpenter and a sacrifice fly to Beltran.
LeCure has now given up two runs in two of this last three outings -- this after recording 10 straight scoreless appearances.
"These guys are never out of a ball game," Arroyo said. "Some teams you have down, 4-2, you feel like the game's over, especially with the back end of our bullpen. But these guys fight their way, man. The whole lineup poses some problems. Holliday is the lynchpin to that whole lineup. He just brings so many weapons to the plate, and it just makes everybody better. Every guy in that lineup has a hitting streak going, so it's not easy to navigate for nine innings."
"These are two teams that play the game hard, play the game the right way, have good pitching staffs, good lineups," Descalso said. "That's what baseball's all about. It was a well-played game tonight and we were fortunate to come out on top."