Game 1 will be played on Wednesday at Citizens Bank Park and will air on TBS and MLB.TV at 5:07 p.m. ET.
The Phillies posted the NL's best record at 97-65 and have won the NL East Division four straight years. The Reds won 91 games and are experiencing the postseason for the first time since 1995.
"We've been the underdog all season. I love the underdog," pitcher Travis Wood said. "You get overlooked and when they slip up, you can beat good teams. We have a young and veteran group in here. We're going to be fired up to play. We're going to give them a run for their money."
It just so happens that Reds manager Dusty Baker has a painting in his office of him, with toothpick in mouth, watching the cartoon character Underdog flying over Great American Ball Park. The mighty mutt had championship banners in tow.
"I always look at the painting in my office whenever I think about playing a team people don't expect us to beat," Baker said. "Hopefully we can shock them in a short series. Anything can happen, especially when you're [among] the last eight."
The Braves took an 8-7 win over the Phillies while the Padres were defeated by the Giants, 3-0, on Sunday. That gave the 92-71 Giants the NL West title and the 91-71 Braves claimed the NL Wild Card berth. Since the Phillies can't play a division rival in the first round of the playoffs, they get the third-seeded Reds.
"The Phillies are kind of the Yankees of the National League," Baker said. "They're the reigning champs two years ago in the National League. They were world champs a couple of years ago. They have an outstanding team."
Game 1 will feature Reds pitcher Edinson Volquez against Phillies ace and 21-game winner Roy Halladay. In his first half-season back from Tommy John surgery, Volquez was 4-3 with a 4.31 ERA in 12 starts. He finished with a 1.95 ERA over his last four starts. One other sign of optimism is his 2-0 record and 0.73 ERA in two career starts vs. Philadelphia.
Friday's Game 2 at 6:07 p.m. ET pits Reds 17-game winner Bronson Arroyo against Roy Oswalt. And on Sunday when the series comes to Cincinnati, Johnny Cueto will pitch for the Reds against Cole Hamels.
Despite their 2-5 record, the Reds played the Phillies well in the regular season. Both wins came at Great American Ball Park, but it was the four-game sweep at Philadelphia going into the All-Star break that provided a character test. All of the losses were by two runs or fewer, with three in extra innings and two by 1-0 scores . After that series, the Reds went unbeaten in the next seven series, but they obviously have no room to take such a step back.
"Losses are losses. But also, that's the regular season," first baseman Joey Votto said.
The Phillies played those latter games without one of their best players, second baseman Chase Utley, and were also missing third baseman Placido Polanco. Both have since returned.
Cincinnati faced Halladay on July 10 at Citizens Bank Park and notched five hits over nine innings before losing, 1-0, in 11 innings. But they beat him on June 30 at Great American Ball Park. Despite his complete game, he gave up four runs and 13 hits during a 4-3 Reds win.
As a team, the Reds batted .272 against Halladay in the two games.
"He's one of the best pitchers in the game, everybody knows that," Reds right fielder Jay Bruce said. "But we're one of the best offenses in the game. We just have to continue to execute like we have been, stick to our approach and see what happens."
The Reds finally beat Oswalt twice this season while he was with the Astros as Oswalt posted a 6.75 ERA and they hit .347 as a team. Until this season, Oswalt was 23-1 vs. the Reds and they hadn't beaten him since 2006.
Hamels could prove to be the toughest riddle of all since he is 6-0 with a 1.07 ERA in seven starts lifetime vs. the Reds with two complete games.
"Getting off to a hot start and getting going against these guys in Philly is going to be huge for us," Bruce said. "If we do what we're capable of, we'll be fine."