Guillen homered and drove in the go-ahead run with an RBI single in the seventh to lift the Mariners past the Texas Rangers 4-2 on Friday night.
Seattle has won seven of eight, and 19 of 26 since a season-long seven-game losing streak. The Mariners entered Friday night's game one game behind the Los Angeles Angels in the American League West and two games ahead of the New York Yankees for the wild-card lead.
Guillen is coming off an injury-riddled 2006 season in which he played only 69 games with the Washington Nationals. The season was cut short when he had reconstructive elbow surgery last July 25.
But Guillen, who also battled leg injuries earlier this season, is hitting .344 with six home runs and 19 RBI in August.
"I've gone through a lot since last year," Guillen said. "It has taken a lot of hard work and dedication to come back. I had to change the way I swing because I was so sore. But all the soreness is gone now."
Guillen hit his 19th home run with two outs in the first inning, then broke a 2-all tie with a hit that scored Ichiro Suzuki.
Then in the eighth, Guillen made a nice running catch in right on Michael Young's liner to end the eighth.
That preserved the win for Felix Hernandez (10-6). He allowed three hits and struck out seven in six innings to improve to 4-0 over his last six starts.
Hernandez wanted to go out for the seventh inning because he was confident Seattle's offense -- which is hitting .333 in August -- would get him the win.
"If I gave up another run, I knew they were going to score some runs for me," Hernandez said.
David Murphy hit a two-run homer in the fifth for Texas, which lost its second straight after scoring 39 runs -- including a record 30 in the opener -- in a doubleheader sweep at Baltimore on Wednesday.
Kevin Millwood (8-11) was the hard-luck loser. He allowed four runs and 13 hits in 8 2/3 innings, falling just shy of the Rangers' first complete game of the season.
Millwood had won five straight starts at home since June 6.
"It was a tough night," Millwood said. "Those guys are swinging the bats as well as anybody I've seen all year. To hold them down and give us a chance felt pretty good."
Ichiro, who had three hits for his 61st multihit game of the season, had a one-out infield single in the seventh. He took second on a grounder to set the stage for Guillen.
Guillen lofted a soft single to right off Millwood to plate Ichiro and put the Mariners ahead 3-2.
Millwood gave up 10 hits and struck out one without walking a hitter. He had retired 13 of 14 hitters before Ichiro started the winning rally.
J.J. Putz pitched a perfect ninth for his 37th save in 39 opportunities.
Morrow ran into trouble in the eighth when Travis Metcalf singled, was sacrificed to second and took third on a wild pitch.
But the Rangers could not get the tying run home as Ian Kinsler popped up to shallow center and Young lined out to right.
Morrow has now pitched 17 consecutive scoreless innings over his last 15 outings.
"I threw a lot of fastballs," Morrow said. "I just tried to stick to by best pitches."
Hernandez retired 14 straight batters after giving up a single to Frank Catalanotto leading off the bottom of the first.
Jason Botts broke Hernandez's momentum with a check-swing single to left. Murphy then lined a two-run homer to right to tie the game at 2.
It was Murphy's first home run of the season and second of his career.
"(Hernandez) had some great stuff," Washington said. "We had opportunities. We just couldn't cash them in."
Guillen's solo shot in the first put Seattle on top 1-0.
Raul Ibanez had three hits for Seattle.
- Washington announced after the game that Jamey Wright will start Saturday night's game for the Rangers.
- The Mariners had 13 hits and have posted eight straight games of at least 10 hits or more.
- Murphy's other home run came last Sept. 17 off New York's Jaret Wright.