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DENVER -- Troy Tulowitzki's stunning power surge could be all in the wrists.

Tulowitzki homered twice -- he has eight in his past eight games -- and Jorge De La Rosa struck out a season-high 10 in six innings to lead the Colorado Rockies past the Arizona Diamondbacks 13-4 on Friday night for their season-best eighth consecutive victory.

Tulowitzki doubled and walked in going 3-for-3 with four runs scored, matching a career best. He is batting .444 in his past eight games -- during which he has had two of his three career multihomer games -- and has reached 20 homers in a season for the third time in his career.

The latest power display coincides with a return to normalcy in the left wrist that he fractured when hit by a pitch June 17. He missed 33 games before returning July 27.

"I think he's physically beginning to feel better and better every day as far as that wrist is concerned," manager Jim Tracy said. "Because that bat is going through the zone again in a hurry."

Tulowitzki agreed his wrist is the best it has been since coming back from the fracture.

"I've definitely felt better as of late," he said. "In batting practice, I can tell my power is starting to come back. Sometimes, you get hurt and you've got to play with it and realize what you can and can't do. Before I felt like the power wasn't there, so I was more spraying the ball around. Now, I feel like I can pick my chances to try to take a swing where I can hit a home run."

Diamondbacks manager Kirk Gibson said Tulowitzki made it tough on his club.

"He's hot,"Gibson said. "He's seeing the ball real well. We got around [Carlos] Gonzalez well tonight. That's one of the strengths of their team, if you get around the first guy, you got to get around the second guy. We tip our hat to him. We'll have to make better pitches at him tomorrow."

Tulowitzki's barrage backed De La Rosa (7-4), who struck out the side in the fourth inning and fanned at least one batter in each of the innings he pitched in winning his third consecutive decision.

He allowed two runs and five hits, including Chris Young's 25th homer in the second. But De La Rosa also hit an RBI double in a six-run third inning to help the Rockies stay close in the NL West race and the NL wild-card chase.

The Rockies capitalized on an erratic outing by Joe Saunders (2-5), who gave up seven runs and five hits in 2 1/3 innings, his shortest outing of the season. He struck out one and walked four, the last with the bases loaded, in dropping a September start for the first time in his past 12 outings in the month dating to 2007.

Colorado broke the game open in the third, with Tuolowitzki doubling to right to drive in the first of the Rockies' six runs in the inning. Saunders walked the next three batters, leaving in favor of D.J. Carrasco after forcing in a run with his final walk. Miguel Olivo greeted Carrasco with a bases-clearing triple and De La Rosa doubled over the head of left fielder Rusty Ryal to drive in the inning's sixth run for 8-1 lead.

The Diamondbacks added a run in the fourth on pinch-hitter Cole Gillespie's groundout but Tulowitzki answered in the bottom of the fourth with a drive off Carrasco that sailed 15 rows into the left-field bleachers.

Eric Young Jr. and Ryan Spilborghs had RBI singles around Tulowitzki's second homer in the sixth inning, off reliever Zach Kroenke, who was making his major league debut.

Game notes

Olivo's triple in the third was his career-best sixth of the season. He had five last year. ... It was the fifth time in his career De La Rosa has had 10 or more strikeouts in a game. His career high is 12. ... Saunders had allowed only four runs in 15 innings over his two previous starts. ... Todd Helton's double in the sixth was the 525th of his career, tying him with Ted Williams for 35th on the all-time list. ... Rockies reliever Edgmer Escalona pitched a scoreless eighth in his major league debut. ... The Diamondbacks are 11-8 in their past 19 games against NL West teams.