Rockies 10, Reds 9: Drew Stubbs slugged a walk-off three-run homer to cap a five-run rally in the ninth inning as Colorado stunned Cincinnati in the first game of a day-night doubleheader.Reds closer Aroldis Chapman entered in a non-save situation to begin the ninth but walked all four batters he faced to allow the Rockies to pull within 9-6. J.J. Hoover (1-9) took over and allowed a sacrifice fly and recorded a second out before Stubbs launched the game-winner just over the wall in left-center.Corey Dickerson and Charlie Blackmon had solo homers and Nolan Arenado went 4-for-4 with an RBI for Colorado, which improved to 1-26 at home when trailing after eight innings. Jay Bruce homered among his three hits and drove in three runs, and Zack Cozart delivered a two-run single and scored twice for the Reds, who fell four games back in the race for the second wild-card spot in the National League.Bruce's two-run blast, Cozart's hit and a solo homer by Kris Negron helped Cincinnati score seven consecutive runs and take a 7-3 lead into the seventh. Dickerson went deep as part of a two-run rally in the seventh for Colorado to make it 7-5 before Bruce and Brayan Pena ripped run-scoring hits against Rex Brothers (4-5) in the ninth to put the Reds up four.Stubbs and Dickerson had back-to-back doubles in the first to start the scoring against Mat Latos, who gave up three runs in five innings, and Arenado added an RBI single later in the frame. Blackmon homered in the second to give the Rockies a 3-0 lead but it was not held by Jordan Lyles, who surrendered five runs in five innings.GAME NOTEBOOK: Reds All-Star 3B Todd Frazier (back) missed his second straight game while Rockies RF Michael Cuddyer (shoulder) returned to the lineup after missing more than two months, going 1-for-5 with a run scored. ... Colorado retired longtime first baseman Todd Helton's No. 17 in a ceremony prior to the game. ... Reds RHP Dylan Axelrod opposes Rockies LHP Yohan Flande in the nightcap.