DENVER, CO - AUGUST 05: Javier Baez #9 of the Chicago Cubs grounds out against Franklin Morales #56 of the Colorado Rockies in the fourth inning at Coors Field on August 5, 2014 in Denver, Colorado. The Cubs defeated the Rockies 6-5 in 12 innings. (Photo by Doug Pensinger/Getty Images)
DENVER - Javier Baez homered in the 12th inning in his major league debut and the Chicago Cubs beat the Colorado Rockies 6-5 on Tuesday night.
Wellington Castillo also homered for the Cubs, who have won four of five.
Baez, a prized prospect called up before the game, struck out in three of his first five at-bats before hitting Boone Logan's first pitch of the 12th an estimated 414 feet into the Rockies' bullpen.
Hector Rondon (3-3) blew his fourth save but got the win and Carlos Villanueva picked up his second save.
Both teams scored a run in the 11th to extend the game.
Nolan Arenado homered and Logan (2-2) took the loss for the Rockies, who have dropped five straight.