DENVER (AP) RRyan McMahon hit a tiebreaking homer in the sixth inning, and the Colorado Rockies beat the Miami Marlins 3-2 on Monday night in a matchup of the NLs worst teams. Colorado (49-83) and Miami (47-84), which entered the majors together in 1993, are both rebuilding and fielded lineups featuring young players. Griffin Conine, the son of former Marlins franchise icon Jeff Conine, made his major league debut as a pinch-hitter in the fifth inning. He struck out. McMahon led off the sixth with a 438-foot drive to center field, his 17th homer of the season, on a 95 mph fastball from Edward Cabrera (2-6). It was the only extra-base hit of the game. The guy was throwing 97 mph changeups tonight, said McMahon, who snapped a 20-game Jean Segura Jersey homerle s streak. I put a good swing on it and I was happy it went out. The Rockies bullpen worked four scorele s innings. Jake Bird (2-2) pitched the sixth and Tyler Kinley got the final three outs for his seventh save. A lot of times when you go to the bullpen and use four guys they have to be flawle s in a one-run game and they were today, manager Bud Black said. Rockies starter Ryan Feltner, who was forced out of a start after one inning on Aug. 7 and landed on the 15-day injured list with a right shoulder strain, held the Marlins scorele s through four innings but yielded Jesus Sanchezs two-run single in the fifth. They were starting to chip away a little bit in the fifth but I still felt comfortable with my stuff, Feltner said. Fastball felt unexpectedly good today so we decided to throw more. Feltner hasnt won since April 10 at Toronto, a winle s streak of 21 starts. The Rockies tied it in the bottom of the fifth on Aaron Schunks RBI groundout and Jake Caves run-scoring single. Cabrera gave up six hits and struck out eight in 5 1/3 innings. I thought he did good, manager Skip Schumaker said. Plenty enough for us to win at Coors Field. Kept the ball in the ballpark for the most part, just one solo home run. Youll sign up for that any day. I dont see anything he did wrong, just a couple of outs from a quality start. TRAINERS ROOM Marlins: SS Xavier Edwards (sore back) was placed on the 10-day injured list, retroactive to Saturday. Rockies: OF Brenton Doyle was scratched with right leg sorene s. ... To make room for Feltner on the roster, LHP Lucas Gilbreath (left shoulder inflammation) was placed on the 15-day IL. ... SS Ezequiel Tovar was out of the lineup but Black said he should be back Tuesday night. UP NEXT Marlins RHP Roddery Munoz (2-7, 5.98 ERA) will start opposite Colorado RHP Cal Quantrill (8-9, 4.56) on Tuesday. Jesus Tinoco Jersey