Rockies 8, Giants 7: Pinch hitter Justin Morneau capped a four-run eighth inning with a two-run double as Colorado used another dramatic comeback to complete its first three-game sweep in San Francisco since September 2008.Troy Tulowitzki clubbed a two-run homer among his three hits, Drew Stubbs and Mike McKenry each had RBI hits during the decisive eighth and Charlie Blackmon collected three hits to lift the Rockies to their fifth consecutive victory. Matt Belisle (2-2) pitched an inning and LaTroy Hawkins secured his 14th save for Colorado, which staged ninth-inning rallies to win the first two games of the series. Starting pitcher Madison Bumgarner, Hector Sanchez and Pablo Sandoval each homered while Tyler Colvin, Ehire Adrianza and Hunter Pence had RBI singles for the National League West-leading Giants, who blew a four-run lead after six innings en route to their sixth defeat in seven games - all at home. Juan Gutiérrez (1-2) allowed four runs in two-thirds of an inning before Javier Lopez surrendered Morneau's go-ahead hit.Tulowitzki, who raised his batting average to a major league-best .362, homered in the third to cut the deficit to 3-2, but back-to-back blasts by Sanchez and Sandoval in the fourth and Bumgarner's second homer of the season leading off the fifth made it 6-3. Colvin extended the lead with a run-scoring single before pinch hitter Josh Rutledge started the Rockies' comeback with an RBI double in the seventh that got the club within 7-4.After Tulowitzki opened the eighth with a single off Gutiérrez, Stubbs delivered a triple and scored on McKenry's infield single to make it 7-6. McKenry advanced to third on DJ LeMahieu's fielder's choice before Morneau greeted Lopez with a booming double to left to plate the tying and winning runs.GAME NOTEBOOK: Giants C Buster Posey exited the game after taking a foul tip off his mask in the fourth. Posey was removed for precautionary reasons in the bottom of the inning and was being evaluated, the team said. ... Tulowitzki, who injured his toe in Friday's series opener, tied Miami's Giancarlo Stanton for the NL home run lead with his 18th in the third. ... LHP Bumgarner worked seven innings, giving up four runs and four walks while striking out nine for the Giants, who will open a five-game road trip at the Chicago White Sox on Tuesday. RHP Juan Nicasio was tagged for three runs on four hits and four walks in two-plus innings for the Rockies, who continue their six-game road trip at the Los Angeles Dodgers on Monday.