CHICAGO -- Carlos Pena focused on staying calm when he came to the plate with two runners on in a tie game Wednesday night.
That quiet moment of concentration quickly turned into a jubilant jaunt around the bases.
"I think sometimes in those situations we tend to get a little bit anxious and try to do too much," he said. "So my whole role there was stay under control and not try to save the world, you know.
"Usually when we're able to stay calm we give ourselves the best opportunity possible to succeed."
Castro sparked the winning rally with a leadoff single against Logan Ondrusek (4-5). Reed Johnson moved Castro to second with a sacrifice before the Reds decided to intentionally walk Ramirez and bring in left-hander Bill Bray to face the lefty-batting Pena.
Big mistake, at least Wednesday night.
Pena pulled Bray's first pitch onto Sheffield Avenue for his 26th homer and third in his last eight games.
"That was a good home run by Pena, huh," Cubs starter Ryan Dempster said. "Wow. I would have liked to have seen that with no wind, let alone wind blowing out. Sure did hammer that."
The big first baseman began the day with a .135 average against lefties, and Bray was holding lefty batters to a .188 average. But this time it didn't work out for the Reds.
"We had the matchup we wanted," Reds manager Dusty Baker said. "Billy's been great against lefties all year. They're hitting .190 off of him, Pena's hitting .130 off of lefties, but he made a mistake and hung a slider that didn't slide, it just spun up there. ... He didn't miss it."
The Reds chased Dempster with three consecutive hits to begin the seventh inning, including pitcher Johnny Cueto's leadoff infield single. Votto hit a sacrifice fly off James Russell to trim Chicago's lead to 3-2 and Jay Bruce followed with a bouncer down the third-base line for an RBI double.
The Cubs brought the infield in for Alonso, who hit a fly ball to medium center field. Johnson got in good position, brought it in, then fired a strong throw to catcher Koyie Hill that cut down Edgar Renteria at the plate.
"I was real fortunate," Johnson said. "When that ball was first hit, my initial thought was it going to be too deep for me to have a chance at him, and then obviously the wind took care of the rest and just kind of allowed me to move through the play."
Chicago also got a big inning-ending double play in the sixth when Ramon Hernandez lined to shortstop Castro, who threw to LeMahieu before Alonso could get back to second base.
Dempster allowed 10 hits -- matching a season high -- and is winless in his last five starts.
Pena doubled and scored on LeMahieu's hit in the fifth, and the Cubs went ahead 3-1 on Ramirez's clutch double in the sixth.
Cueto allowed seven hits in seven innings and his major league-leading ERA increased from 2.29 to 2.36.
"I want to (win it)," Cueto said of the ERA title. "I put all my best to get it done. Sometimes you throw seven innings and instead of going down, it goes up. Of course I want to (win it)."
Cincinnati pushed across a run after Dempster quickly retired the first two batters of the game. Votto hit a well-placed fly ball to left that landed in front of Alfonso Soriano, then rolled past him for a triple. Bruce walked before Alonso hit a liner up the middle for an RBI single.
2B Darwin Barney left the Cubs to be with his wife for the birth of their second child. Manager Mike Quade said he expects Barney will rejoin the team Friday in New York. ... Reds RHP Mike Leake will make one more start this season. Baker said the team will use a six-man rotation for one turn, inserting RHP Edinson Volquez, then Leake will drop out. ... The Cubs and Old Style-maker Pabst Brewing Co. announced the brew that has been available to fans since 1950 will be peddled at the Wrigley Field through 2013. Pabst threatened earlier this year to pull the beer from the ballpark. ... The Cubs are off Thursday before opening a weekend series at the New York Mets. RHP Casey Coleman (2-7, 6.61 ERA) is scheduled to face Mets RHP Mike Pelfrey (7-11, 4.68) on Friday night. ... The Reds are off Thursday, then begin a three-game series at Colorado on Friday night. Reds RHP Homer Bailey (7-7, 4.57 ERA) and Rockies RHP Jhoulys Chacin (11-10, 3.60 ERA) will meet in the opener. ... A fan in the second deck made a solid catch on a foul ball in the fifth inning, but one of his friends lost his hat over the railing in the resulting celebration, drawing guffaws from the crowd of 36,797. He went down to the lower section to retrieve his cap, and got a small ovation from his section when he returned.