Tim Lincecum was hoping to stop the worst skid of his career when he pitched in front of family and friends during his homecoming Saturday night.

It ended up being more of the same.

Casper Wells and Jesus Montero greeted Lincecum with long first-inning home runs, Franklin Gutierrez's infield single in the sixth gave Seattle the lead for good and the Mariners snapped a six-game losing streak with a 7-4 win over the San Francisco Giants.

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. Brendan Ryan followed with a two-run single to center.

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.

Lincecum gave up five runs and five hits, struck out six and walked two. The right-hander is 0-6 with a 6.44 ERA in nine starts since his last victory April 28 against San Diego.

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.

Lincecum settled down after Montero's eighth homer and his teammates started to help out. The Giants got a pair in the third on RBI singles from Ryan Theriot and Buster Posey and scored twice more in the fourth, with Theriot and Melky Cabrera collecting run-scoring hits to give the Giants a 4-2 lead.

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 greeted Affeldt with a line drive single. 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 instead of tagging Saunders, 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.

NOTES: Millwood left Seattle's no-hitter with a strained groin. He was pushed back a few days in the rotation and gave up three earned runs in five innings. .... Suzuki's infield single in the fifth gave him 2,499 career hits in the majors. ... San Francisco is now 2-12 in games started by Lincecum this season.