SEATTLE -- After starting pitcher Chad Bettis turned in one of the best starts of his career and rookie catcher Dustin Garneau provided the big hit with a tiebreaking homer in the seventh inning, the Colorado Rockies were one out from finishing off the Seattle Mariners on Friday night.

And closer John Axford wasn't going to fastball his way to the finish.

Having touched 100 mph on his fastball earlier in the inning, Axford turned to his rarely used curveball to strike out Seattle third baseman Kyle Seager for the final out of the Rockies' 4-2 win on Friday night.

"The curveball off an elevated heater," Garneau said, "that's a tough pitch to hit."

Garneau broke a scoreless tie with a three-run homer in the seventh inning and Bettis threw seven scoreless innings before Axford finished off Colorado's second consecutive victory -- and his 22nd save of the season -- by stranding two runners on base with the Seager strikeout.

"Seager's a threat; he's dangerous," Axford said of the Seattle third baseman who had cut the deficit to 3-2 with an eighth-inning homer. "Anything you can do to throw him off. I'd only thrown three or four curveballs all year, so that was the time to do it."

Garneau's second career home run -- his first came Wednesday night -- also snapped a string of 24 consecutive scoreless innings by Mariners pitchers. He gave the Rockies a 3-0 lead during a five-run seventh inning that chased Seattle starter Hisashi Iwakuma from the game.

"I lucked out," Garneau said with a chuckle. "I don't really know what happened, and it went over the fence."

Bettis (7-5) allowed three hits without giving up a run in seven innings and left the game with a 3-0 lead. Reliever Christian Friedrich came on in the eighth and walked the first batter he faced before Seattle third baseman Kyle Seager hit his 24th home run of the season, a two-run shot that pulled the Mariners within 3-2.

Five Colorado relievers finished off the win, with Axford posting his 22nd save of the season after a 27-pitch bottom of the ninth.

After the Rockies added an insurance run on a wild pitch, scoring shortstop Daniel Descalso, in the top of the ninth, Axford took over with a 4-2 lead in the bottom of the inning. He gave up a one-out single to Seattle shortstop Brad Miller and a two-out walk to put the tying run at first base. Seager drew a full count before Axford struck him out with the curveball.

"We had the guys at the plate we wanted," Mariners manager Lloyd McClendon said. "We just couldn't get it done. That's baseball."

The Rockies (59-82) used five seventh-inning hits, the biggest coming on Garneau's three-run homer, to take a 3-0 lead.

The Mariners came back to score two runs on Seager's homer in the eighth. His 24 home runs this season are one short of his career high, which he accumulated last year.

Iwakuma was every bit as dominant as Bettis for six innings before he hit a wall in the seventh. The Rockies had five one-out hits in a row to chase Iwakuma from the game after 97 pitches.

Iwakuma (7-4) allowed eight hits and three runs in 6 1/3 innings.

"I don't think he hit a wall," McClendon said. "He elevated some pitches -- obviously, the backup slider. He'd been throwing extremely well; he just couldn't keep the ball down (in the seventh)."

Seattle (68-74) lost for only the third time in 10 games and is now one loss from matching its total from the 2014 season.

Colorado left fielder Corey Dickerson, designated hitter Justin Morneau and Descalso all had two hits as the Rockies piled up 11 of them on Seattle pitchers.

Neither offense could get much going in the early innings. The Mariners left runners stranded at second base in the second and third innings, and Colorado wasted a leadoff double in the fourth.

Seattle got a leadoff runner on in the second, courtesy of an error on Colorado third baseman Nolan Arenado, but ended up leaving runners stranded at first and second base.

One inning later, center fielder James Jones got an unconventional double with one out, having squibbed a ball up the middle and under the glove of Descalso before legging out two bases, but the Mariners couldn't bring in a run.

The Rockies' best early chance came in the top of the fourth when Dickerson led off with a double. Iwakuma intentionally walked slugger Carlos Gonzalez with one out and then got out of the inning as the game remained scoreless through the fifth.

Bettis threw 98 pitches in seven innings and admitted afterward that he was tiring.

"I would have liked to stay out in the eighth, but at the same time I was running out of juice," he said. " ... It was probably the right call."

The announced crowd was 19,876, marking the fourth time in as many games during the current homestand that Safeco Field has failed to hit 20,000.

NOTES: Colorado SS Jose Reyes was not in the lineup Friday because of a left Achilles' tendon strain, marking the second consecutive day he did not start. It's the first time since Reyes was traded from Toronto that he's been out of the lineup on back-to-back days. ... Seattle still hasn't officially named a starter for Sunday's series finale, but LHP James Paxton is the most likely candidate. Paxton has been on the disabled list since May 29 and would have to be activated before making the start. "It's trending toward Paxton starting on Sunday," Mariners manager Lloyd McClendon said before Friday's game. ... The Mariners shut out Texas on Wednesday and Thursday and went into the Colorado game seeking their first three-game shutout streak in club history. ... Mariners OF Franklin Gutierrez, who had been out of action for six days because of a pelvic condition, was not in the lineup Friday but was available to pinch-hit. McClendon said he hoped to have Gutierrez in the lineup this weekend.