The series opened on a sunny afternoon in St. Louis, before 47,078 fans watching the Nationals' first playoff game since October 19, 1981, when they were the Montreal Expos.

The Nationals struck first on an RBI single by Kurt Suzuki in the second inning with two on off of Adam Wainwright, but the Cardinals responded with two of their own, as 21-game winner Gio González walked three to load the bases, then threw a wild pitch, before walking another to load the bases and allowing a sacrifice fly to Jon Jay, helping St. Louis score without the benefit of a hit.

The score stayed 2–1 until the top of the eighth, when Tyler Moore delivered a two-out, pinch-hit single off of Marc Rzepczynski to give the Nationals a 3–2 lead they would not relinquish, both runs charged to Mitchell Boggs, as Tyler Clippard and Drew Storen sealed the deal out of the bullpen for the first playoff win for the franchise in 31 years.

In the eighth, Komza doubled with one out off of Sean Burnett and scored on Jay's two-out triple, then Beltran's second home run of the game made it 11–4.

The Cardinals added to their lead on Daniel Descalso's sacrifice fly after a hit-by-pitch and double off of Craig Stammen, who increased his ERA in the series to 11.57.

Fernando Salas and Joe Kelly pitched a scoreless eighth and ninth respectively to put the Cardinals one win from the NLCS.

In the bottom of the ninth, Jayson Werth, on the 13th pitch of a lead off at-bat against Lance Lynn, lined a homer into left field, giving the Nationals a 2–1 win and forcing a Game 5.

In the first, Jayson Werth hit a leadoff double and scored on Bryce Harper's triple before Ryan Zimmerman's home run put them up 3–0.

In the fifth, St. Louis scored two more runs on a wild pitch and walk to Allen Craig, but wound up stranding the bases loaded.

In the seventh, the Cardinals tacked on another run off Edwin Jackson appearing in relief on two days' rest on Holliday's RBI groundout.

The Cardinals continued to chip away at the Nationals' lead when Daniel Descalso homered off Tyler Clippard to make it 6–5 Washington.

The Nationals got a much-needed insurance run in the bottom of the eighth on Kurt Suzuki's RBI single off Jason Motte, and sent out Drew Storen, who had recently replaced Clippard as the team's closer, to pitch the ninth.

In the top of the first, Brandon Belt made an amazing catch, leaping over the fence in foul territory and into the crowd, but holding on for the second out to help Cain pitch a 1–2–3 inning.

Scott Rolen picked up the ball and threw it away, but Phillips made a great diving stop to keep Blanco off second and the Giants from scoring anymore.

In the ninth, the Reds added two runs off of Santiago Casilla with two on via an RBI single from Phillips and a passed ball by Posey.

The Reds put the game out of reach in the eighth when a leadoff single and subsequent walk was followed by Jay Bruce's two-run double off of Jose Mijares.

After Santiago Casilla got one out, Hanigan's single, Drew Stubbs's triple, and Brandon Phillips's double off of Mota scored a run each.

Homer Bailey, who had pitched a no-hitter just two starts before, was flirting with another one, not giving up a hit through 5+2⁄3 innings before Marco Scutaro broke it up with a two-strike single.

Ángel Pagán hit the second pitch of the night, from emergency starter Mike Leake, over the right field wall for a lead-off home run, the first in Giants postseason history.

[27] Pitching for the Giants, Barry Zito struggled early, allowing a two-out single to Joey Votto, then walking three consecutive Reds hitters in the bottom of the first to force in a run.

Zito continued to struggle, needing 76 pitches to complete just under three innings of work and allowing a home run to Ryan Ludwick in the third that made it 3–2 Giants.

In the fifth, Back-to-back doubles by Joaquín Árias and Pagán off of Leake, followed by a Pablo Sandoval sacrifice fly off of Sam LeCure gave the Giants a 5–2 lead.

With two men on and the Giants clinging to a two-run lead, Sergio Romo retired Jay Bruce on a harmless fly ball to left after a 12-pitch duel.

Romo then settled down and struck out Scott Rolen (in what would be the final at-bat of his Hall of Fame career) to give the Giants the victory.

Cincinnati joins the 1984 Chicago Cubs and 1981 Houston Astros as the only National League teams to blow a 2–0 lead in a best–of–five series.