Giants win division series with 6-4 victory over Reds October 11, 2012 -- Updated 2330 GMT (0730 HKT) The San Francisco Giants celebrate their Series-clinching victory. NEW: Jayson Werth's walkoff homer propels Nationals to win over Cardinals NEW: The two teams meet in a deciding game Friday Giants become first NL team to rally from a two-game deficit in a division series Buster Posey drove in four of the Giants' runs with a grand slam (CNN) -- Buster Posey hit a grand slam home run to lead the San Francisco Giants to a 6-4 National League Division Series-clinching victory Thursday over the Cincinnati Reds. Brandon Crawford and Angel Pagan also drove in runs as the West champion Giants defeated the Reds three games to two. The Giants became the first NL team to trail 0-2 in a division series before winning three consecutive games. Under Major League Baseball's new playoff format, San Francisco had to win three road games to do so. Giants pitcher Matt Cain gave up three runs in 5 2/3 innings to earn the victory. Mat Latos took the loss. San Francisco next will play the winner of the St. Louis Cardinals-Washington Nationals series. Washington 2, St. Louis 1 Washington's Jayson Werth hit a home run to lead off the bottom of the ninth, keeping the Nationals alive in their National League Division Series with a victory over the St. Louis Cardinals. The two teams will play the deciding contest of the five-game series Friday night. The Nationals used four pitchers who gave up just three hits while striking out 10 batters. Washington's Drew Storen was the winning pitcher, while St. Louis' Lance Lynn was the loser. Adam LaRoche homered for the Nationals in the second inning, while Carlos Beltran hit a sacrifice fly in the third for the Cardinals' only run.