Chris Dickerson had three hits and broke a sixth-inning tie with a two-out RBI double to help the Reds beat the Pirates 3-1 on Thursday night.
"That was a huge at-bat," Dickerson said.
With the score tied 1-all, Corey Patterson doubled to lead off the sixth against Snell (4-10) and moved to third on a ground out. Andy Phillips, pinch-hitting for starter Johnny Cueto, hit a grounder to third and Patterson was tagged out in a rundown after breaking for home.
Phillips advanced to second on the play and scored when Dickerson lined a double into the right-field corner.
The 26-year-old outfielder tried his best to block out the situation during his at-bat.
"I just told myself, once (Phillips) got to second, to relax," Dickerson said. "I took a couple of deep breaths and didn't put too much pressure on myself to succeed."
Dickerson, who made his major-league debut Tuesday, also doubled in the third and tripled and scored in the ninth on a squeeze play.
"I'm kind of speechless," he said. "That was exciting. I felt really comfortable tonight, and that's the most important thing. I worked out the jitters in the first game."
Dickerson was called up from Triple-A Louisville to fill the roster spot created when Adam Dunn was traded to the Arizona Diamondbacks on Monday. He went 1-for-4 with a double, a run and stolen base on Tuesday before sitting out Wednesday's game.
Cincinnati manager Dusty Baker said Dickerson, named the organization's Minor League Player of the Month for July, has brought energy to the team.
"That's what young people do," he said. "And he's brought some speed, whether it's covering ground in the outfield or on the bases. It's great."
Javier Valentin homered in his second straight start for the Reds, who took two of three from the Pirates and won for the fourth time in 19 games. The first baseman, who is 10-for-19 with three home runs in his career against Snell, also walked twice.
The Reds left at least one runner on base in the first six innings, stranding nine for the game, and failed to take advantage of five walks from Snell.
"Early on, we left some guys out there, and you're hoping it doesn't come back to haunt you," Baker said.
Snell allowed two runs and six hits in six innings.
"It was a nice game for him," Pittsburgh manager John Russell said. "I can't fault two runs. We were right in the game."
Cueto (8-11) allowed one run and four hits in five innings to break a six-start winless streak. The right-hander struck out seven.
Francisco Cordero, one of five Reds relievers, pitched a perfect ninth for his 23rd save and the 200th of his career.
Andy LaRoche, playing with his brother Adam for the first time as teammates, had an RBI single in the first for Pittsburgh, but also grounded into a double play on a ball hit right at second baseman Brandon Phillips with the bases loaded and one out in the seventh.
"We didn't get them in," Andy LaRoche said. "I wish we could have done more. I hit the double-play ball right at him. I wish I had hit it somewhere else."
Pittsburgh, which has 28 come-from-behind wins this season, left 10 runners on base, including the bases loaded in the first and two on in the fourth and fifth.
"It was one of those nights where we didn't get the big hit like we have," Russell said. "If you look at the game, we should have won."