The San Francisco Giants fended off the Cincinnati Reds in Game Five to advance to the National League Championship Series at Great American Ball Park behind Buster Posey's grand slam on Thursday, 6-4.

The Reds looked almost invincible in the first two games of the National League Divisional Series, but the Giants were able to mount an impressive comeback and win the next three games in Cincinnati.

In Game Five, the Giants headed into the bottom of the fifth inning after posting six runs on starter Mat Latos. Buster Posey's grand slam was a towering shot that gave San Francisco what appeared to be a comfortable lead in the deciding game of the series.

But the Reds' bats would show up while the bullpen surrendered just two hits and no runs in four and two-third innings. Cincinnati had several chances to score, but could only muster four runs. Dusty Baker's squad left two base runners on in the each of the final three innings of the game.

The Reds put up 12 hits in the game, including a home run from Ryan Ludwick in the sixth inning. However, the Reds simply failed on numerous occasions to capitalize on their base runners.

Giants reliever Sergio Romo forced Jay Bruce to fly out to left and struck out Scott Rolen to send the Giants to NLCS after missing the playoffs in 2011.