SEATTLE - Jesus Montero and Casper Wells put a damper on Tim Lincecum's homecoming, powering the kind of start slumping Seattle desperately needed.

Wells and Montero hit long homers off Lincecum in the first inning, Franklin Gutierrez's infield single broke a tie in the sixth and Brendan Ryan followed with a two-run single, leading the Mariners to a 7-4 win over the San Francisco Giants on Saturday night.

Seattle snapped a six-game losing streak that put a spotlight on the Mariners' inability to score at home. Seattle entered Saturday night with the worst home record by percentage and the worst batting average in baseball at home. And while those numbers improved marginally, the 12 hits and seven runs were a far better showing than most of Seattle's miserable homestand.

"It was really nice to see us score some runs here at home and put something together like we did tonight," manager Eric Wedge said.

Lincecum (2-8) was the focal point of the evening thanks to his personal five-game losing streak and his first start in Seattle, where he was a prep star and national collegiate player of the year at Washington. Instead it became another night of frustration for the two-time Cy Young Award winner, who was unable to hold a 4-2 lead and was done just one costly batter into the sixth inning.

Montero led off the sixth with a single and eventually scored the go-ahead run when Gutierrez hit a hard chopper down the third-base line that Joaquin Arias could only knock down. Ryan followed with a two-run single to center.

"I'm going to be the greediest person in the show. I'll take every single one of them," Ryan said. "I'm glad the bat stayed in one piece because I'll be using it tomorrow. It's nice to be on base, but it's nice to just contribute in just some small way, any way but defensively."

Hisashi Iwakuma (1-0) picked up his first major league victory by pitching two scoreless innings in relief of Kevin Millwood, who was making his first start since throwing the first six innings of Seattle's combined no-hitter against the Dodgers on June 8. Charlie Furbush worked the eighth and Tom Wilhelmsen finished for his fourth save in five chances.

Before the game, Lincecum received a rousing welcome back. One fan stood near the bullpen while Lincecum warmed up with a sign reading "In Timmy We Believe." He was given a huge ovation from a large throng of Giants fans as he walked in from the bullpen, but immediately put himself in an early hole.

Wells kickstarted Lincecum's rough night when he sent a 2-1 pitch into the Giants' bullpen in left with one out in the first. Kyle Seager then struck out before Montero showed off the power that made him one of the top prospects in the minors with a shot deep into the second deck of the left-field seats.

"Today was very nice. My timing was good. My swing was good. We were looking for good pitches and we find them," Montero said.

By the time Lincecum took the mound for the fifth, he had retired 10 of 11 batters. But that stretch came to an abrupt end.

Dustin Ackley led off with a single for Seattle's first hit that didn't leave the park. John Jaso walked on four pitches and Ryan's sacrifice put two runners in scoring position.

Ichiro Suzuki's infield single back up the middle was good enough to get Ackley home and cut the Giants' lead to 4-3. Lincecum then bounced a breaking ball in the dirt well in front of home plate, allowing Jaso to score the tying run.

Lincecum was replaced by Jeremy Affledt after Montero opened the sixth with a sharp single to left. Michael Saunders then singled. After a popout, Ackley hit an infield grounder that shortstop Brandon Crawford came in front of the bag at second to field. Saunders briefly stopped running and Crawford threw late to try and get Ackley, who beat the throw to load the bases.

Gutierrez brought home the first run when Arias could only knock down his hard shot and Ryan followed with the first of his two hits. The seven runs were the most for Seattle at home since May 5.

"Right now I'm not happy about the loss but there are silver linings," Lincecum said. "So I'll take those, but I'm still just (angry)."