SEATTLE -- Colorado rookie Dustin Garneau learned quickly from a previous mistake.
Garneau snapped a 0-0 tie with a three-run homer in the seventh and Chad Bettis allowed three hits over seven innings, leading the Rockies to a 4-2 victory over the Seattle Mariners on Friday night.
"It was a little front-door cutter," said Garneau, who was called up from Triple-A Albuquerque in mid-August and now finds himself the most veteran catcher because of injuries to Nick Hundley and Michael McKenry. "He got me my at-bat before where I popped out to the catcher. So, I took a chance and luckily I got my barrel to it."
Bettis (7-5), making his fourth start since coming off the disabled list, struck out six and walked three.
"Honestly, everything was working out for me right out of the gate. It's really nice to have that feeling going into this game," Bettis said. "I felt Garneau and I did a really good job before the game on coming up with a plan on how to attack these guys."
The Rockies had three hits through six innings before breaking through against Hisashi Iwakuma (7-4). After DJ LeMahiue grounded out, Justin Morneau and Ben Paulsen had consecutive singles. Garneau then ripped the first pitch over the wall in left for his second homer, snapping a streak of 24 1/3 scoreless innings by Seattle pitchers.
"I don't think he hit a wall, he elevated some pitches," Mariners manager Lloyd McClendon said. "The one bad pitch was a back-up slider. He was throwing extremely well until then. For some reason, he just left some pitches up and in."
Seattle cut the lead to 3-2 in the eighth off Christian Friedrich when pinch-hitter Shawn O'Malley walked to open the inning and Kyle Seager followed with his 24th home run.
"It was a pitch up and in the zone a little bit, something I could hit and fortunately it worked out," said Seager, who has seven homers in his last 16 games.
The Rockies added a run in the ninth on singles by Daniel Descalso and Charlie Blackmon and a two-out wild pitch by Tony Zych.
After Justin Miller, Boone Logan and Jairo Diaz combined to finish the eighth for Colorado, John Axford pitched the ninth for his 22nd save in 27 opportunities.
The Mariners had two on in the ninth, but Axford struck out Seager on a full-count curveball.
"It shows you that Garneau has a feel for what's going on, and it also shows a lot of nerve from Axford in that situation," Rockies manager Walt Weiss said. "He's got the big curveball. He threw one fastball and Kyle came out of his shoes on it. He saw the fastball pretty well. That's why I think he kept going back to the curveball."
Seattle had an opportunity in the sixth when James Jones singled to open and Seager walked. Nelson Cruz bounced into a double play, sending Jones to third. After Robinson Cano was walked intentionally, Bettis escaped by striking out Mark Trumbo.
"The double play was huge," Weiss said. "We stress it so much. You get two outs with one pitch. You can minimize damage."
TRAINING ROOM
Rockies: Hundley, who left Sunday's game with a stiff neck, was placed on the 60-day DL with a cervical strain. C Tom Murphy was called up from Triple-A Albuquerque.
Mariners: OF Franklin Gutierrez, who had missed the last six games with a strained right groin, struck out as a pinch-hitter in the seventh inning. "Guti's making real good progress," McClendon said before Friday's game.
LHP James Paxton, who has been out since late May with a strained finger on his pitching hand, is expected to start Sunday after experiencing no problems following a bullpen session. "It's trending toward Paxton," McClendon said. "No setbacks, not yet."
UP NEXT
Rockies: LHP Yohan Flande (3-2, 4.65 ERA) will be making his 17th appearance and ninth start. Since moving into the rotation, he is 2-1 with a 4.93 ERA. Tagged for six runs in 4 1/3 innings in his last start against San Francisco.
Mariners: LHP Roenis Elias (4-8, 4.30 ERA), will be making his fourth start since being recalled from Triple-A Tacoma on Aug. 23. He has pitched 5 1/3 innings in each of his last two starts.
AXFORD IN A GROOVE
Axford has not allowed a run in his last nine appearances, covering 8 2/3 innings since Aug. 19. His 22 saves are the most since 2012, when had 35 with Milwaukee, which capped a three-season run when he totaled 105 saves.