DENVER -- The Seattle Mariners sense they are gaining momentum. The Colorado Rockies most assuredly are not.

The Mariners whipped the Rockies 10-4 Tuesday night as Nelson Cruz continued his home run barrage and pinch-hitter Franklin Gutierrez put the visitors ahead for good with a two-run single in the sixth.

A close game turned into a runaway victory as the Mariners scored seven runs in the final four innings.

The Mariners won a third consecutive game for the first time since May 25-27, and they have four wins in five games. To be sure, playing meaningful September games will require some doing for Seattle (50-58).

"We're confident, and to be able to play this good, confidence is there," said Cruz, who extended his hitting streak to 15 games and homered in a fifth straight game. He greeted Scott Oberg in the seventh with his 31st home run of the season, giving Seattle a 6-4 lead.

"Anything can happen. We have a lot of games left. We're just going to play like every game is the last, and hopefully we can get something good from this."

In what became a bullpen battle, the Mariners clearly prevailed.

After Mariners spot starter Vidal Nuno -- he took the turn of J.A. Happ, whom Seattle traded Friday -- worked 3 2/3 innings and surrendered three runs, Rob Rasmussen (1-0) pitched 1 1/3 scoreless innings, retiring the four batters he faced and striking out two to earn his first major league win. He was the first of four Seattle relievers who combined to allow one run in 5 1/3 innings.

"They did a really, really superb job tonight in a tough place to pitch," Mariners manager Lloyd McClendon said.

By contrast, five Rockies relievers allowed a combined seven runs in five innings after Jon Gray departed. Colorado lost for the seventh time in nine games and the 14th time in 16 interleague games.

Gray, the third overall pick in the 2013 draft and the Rockies' top pitching prospect, worked four innings in his major league debut. He left trailing 3-1 but didn't figure in the decision after Colorado catcher Nick Hundley hit a two-run homer to tie the game in the fourth.

Gray worked four innings on 77 pitches and allowed five hits and three runs (two earned) with two walks and four strikeouts. The Rockies will limit Gray's innings for the balance of the season to avoid a stressful increase over his 2014 workload. He arrived in the majors having thrown 114 1/3 innings at Triple-A Albuquerque after throwing 124 1/3 innings last year in Double-A.

"We got the big picture in mind, when you talk about bumping innings from one year to the next," Rockies manager Walt Weiss said. "We don't want to overwhelm him with that. The first inning certainly was a factor, the fact he got so extended."

Gray threw 33 pitches, 16 strikes, in the first, when the Mariners struck for two two-out runs. He issued a one-out walk to third baseman Kyle Seager, who scored on second baseman Robinson Cano's double, and first baseman Jesus Montero followed with a run-scoring single. Gray then allowed three singles, one an infield hit, and an unearned run in the fourth that resulted from shortstop Jose Reyes' throwing error.

"That was a very positive part of the outing," Weiss said, "the fact that he had to labor in the first and settled in and looked real comfortable after that."

Rockies second baseman DJ LeMahieu made a pivotal error with the score 3-3 in the sixth. With no outs and a runner on first, he fielded shortstop Brad Miller's slow roller, a potential double-play ball. However, LeMahieu dropped the ball as he was setting to throw.

That put runners on first and second, and after catcher Jesus Sucre's sacrifice, Gutierrez lined a two-run single off left-hander Christian Friedrich (0-3), putting the Mariners ahead 5-3.

Colorado first baseman Kyle Parker led off the sixth with his first major league home run, trimming the Mariners' lead to 5-4. It came on the second pitch from Mayckol Guaipe, who just entered the game and was called Tuesday from Triple-A Tacoma.

Parker, the 26th overall pick in the 2010 draft, had 18 at-bats in two stints with Colorado last season. The Rockies brought him up for two days in June and recalled him again Saturday.

"He looks a lot more comfortable this time around," Weiss said. "It's been tough for him the last couple times he's been up. It's been spotty play and (infrequent) at-bats, so it's been tough to put anything together like that. He looks a lot more comfortable and a lot more confident this time."

NOTES: Mariners RHP Mayckol Guaipe was recalled from Triple-A Tacoma, and RHP Jose Ramirez was optioned to Tacoma. Guaipe gave up four hits and one run in 1 1/3 innings Tuesday. ... Seattle LHP Charlie Furbush (left biceps tendinitis) is scheduled to throw a bullpen session Wednesday. Barring a setback, he then would go to Triple-A Tacoma for a brief rehab assignment. ... Rockies RHP Gonzalez Germen was optioned to Triple-A Albuquerque to make room on the 25-man roster for RHP Jon Gray, whose contract was selected from Albuquerque and who made his major league debut. ... Rockies RHP Kyle Kendrick (right shoulder inflammation) underwent an MRI exam Monday that revealed no structural damage. ... Colorado RHP Chad Bettis (right elbow inflammation) threw 35 pitches and felt fine in his first bullpen session since going on the disabled list July 19. He is scheduled for a 45-pitch bullpen session Friday at Washington. ... Rockies LHP Aaron Laffey was outrighted to Triple-A Albuquerque.