The Pirates couldn't stop Cincinnati's Johnny Cueto, who drove in the go-ahead run and got his 20th victory on Sunday, a 4-1 win that gave the NL Central title to the St. Louis Cardinals and forced Pittsburgh to settle for a wild card.
Pittsburgh needed to beat the Reds and have the Cardinals lose later in the day at Arizona to pull even for first place and set up a one-game tiebreaker Monday. Instead, Cueto (20-9) settled the division race with eight impressive innings.
The Pirates will head home to play the Giants at PNC Park on Wednesday, with the winner facing the Nationals. Pittsburgh also hosted the wild card game last year and beat the Reds before losing to the Cardinals.
Manager Clint Hurdle indicated that Edinson Volquez likely will start the playoff game.
Jason Bourgeois opened the eighth with a triple off Tony Wilson (10-2). One out later, Cueto came to bat, worked the count full and singled through a drawn-in infield for a 2-1 lead, pumping his fist as he reached first base.
Kristopher Negron added a two-run homer off Justin Wilson.
Cueto gave up six hits in eight innings, including Neil Walker's homer, as he became the first Reds pitcher to win 20 games since Danny Jackson in 1988. He's the first Reds right-hander to win 20 since 1965, when Sammy Ellis and Jim Maloney did it.
Aroldis Chapman pitched the ninth for his 36th save in 38 chances.
The Pirates went all-out to try to win the game, starting Gerrit Cole — their best September pitcher — instead of saving him for the playoffs. Cole did his part, giving up one run and six hits in seven innings and matching his career high with 12 strikeouts.
After talking with team leaders, Hurdle decided to stay with his starting pitching alignment for the playoffs. That meant stick with Cole, who had won his last four starts.
The right-hander had a tough first inning, giving up back-to-back singles by Negron and Brandon Phillips. Todd Frazier's groundout made it 1-0.
Cole went on a streak of retiring 19 of 20 batters, extending his run of impressive September pitching. Cole is 8-1 in 11 career starts during the month.
The Reds played themselves out of contention by going 25-42 after the All-Star break, matching the club record for second-half futility. The 1933 team also had 25 wins after the All-Star game, the fewest in a non-strike season.
Pittsburgh's Josh Harrison went 0 for 4, ending his career-high 15-game hitting streak and hurting his chances for the NL batting title. He started the day at .318, a point behind Justin Morneau, but slipped to .315.