SEATTLE -- Seattle Mariners starting pitcher Hisashi Iwakuma said he didn't have his best stuff Friday night, but it was more than good enough to post his 10th win of the season.

Iwakuma allowed one run in seven innings and got a big boost from catcher Mike Zunino's three-run homer as the Mariners beat the struggling Chicago White Sox 4-1.

"Overall, I'm happy with the win and with the results," Iwakuma said through an interpreter, "but I didn't have good stuff. I didn't have good command of my pitches today."

Despite it all, Iwakuma (10-6) gave up two runs or fewer for the seventh time in a span of eight starts, allowing five hits without issuing a walk while helping extend the Mariners' winning streak to four games.

The only run Iwakuma allowed came on a solo home run from Chicago right fielder Dayan Viciedo, his third home run in as many games.

Zunino answered with a three-run shot during Seattle's four-run fifth inning that put the Mariners ahead 4-1.

"We know if we score a few (runs), we have a chance of winning because of our pitching staff and our bullpen," Zunino said. "We just keep trying to score a few runs."

With the win, Seattle (61-54) kept pace in the American League wild-card race. The Mariners trail Kansas City by a half-game for the second wild-card spot.

Chicago (55-62) has now lost four games in a row, getting outscored 36-5 in the process.

"We just have to keep grinding; it's that simple," White Sox manager Robin Ventura said. "When you're in a funk like this, you have to dig down, be tough about it and find a way to win."

The worst news for the White Sox came in the abbreviated return of center fielder Adam Eaton. Chicago's leadoff hitter returned to the field after missing Thursday night's game with a bruised back but barely made it through the first at-bat of the game.

Eaton saw eight pitches before hitting a grounder to third base, and he was in so much discomfort that he didn't make it halfway to first base on the throw. Eaton, who felt pain in his right rib cage, gingerly walked off the field and was replaced by Leury Garcia in center field in the bottom of the first.

"I think it was maybe the first or second swing of the at-bat," Eaton said after the game, adding that he felt fine during batting practice before the game. "I felt it pretty heavily. I tried to take a second out of the box, and then when I went back in there it was just as painful. When I hit the ball, I couldn't even run to first. So I knew right away that it wasn't good."

Ventura said the extent of the injury won't be known immediately.

The White Sox jumped out to a 1-0 lead on Viciedo's solo shot in the fourth inning. Seattle responded with Zunino's three-run homer in the fifth that put the Mariners ahead 3-1. After right fielder Chris Denorfia walked and first baseman Logan Morrison reached on a dropped pop fly by Chicago third baseman Conor Gillaspie, Zunino hit a 2-0 pitch into the right-field seats for his 18th home run of the season.

"Hopefully, it's something for me to build on for the rest of the series," said Zunino, who went 1-for-4 with three long flyouts to the warning track.

Seattle opened a 4-1 lead later in the fifth inning when designated hitter Kendrys Morales hit a sacrifice fly with the bases loaded to score shortstop Chris Taylor from first base. Two of the Mariners' runs during the four-run fifth were unearned, thanks to Gillaspie's error -- his second in two games.

White Sox starter Jose Quintana allowed seven hits and four runs in 5 2/3 innings, but only two of the runs were earned. Quintana (6-8) suffered his first loss since June 13.

Iwakuma joined teammates Felix Hernandez and Chris Young to give the Mariners three 10-game winners this season.

Mariners closer Fernando Rodney posted his 32nd save of the season after pitching a scoreless ninth.

NOTES: Chicago activated RHP Zach Putnam from the 15-day disabled list Friday. The White Sox had a roster spot available after optioning RHP Andre Rienzo to Triple-A Charlotte late Thursday night. Putnam pitched a scoreless eighth inning Friday. ... The Mariners, who optioned LHP Roenis Elias to Triple-A after his Thursday start, promoted LHP Lucas Luetge to add another arm to the bullpen until Seattle names a Sunday starter. ... Seattle UT Willie Bloomquist underwent microfracture surgery on his knee Friday, effectively ending his season. Bloomquist, 36, was scheduled to undergo arthroscopic surgery, but team doctors discovered extensive damage to his right knee and performed a more extensive procedure. Bloomquist could be ready to rehab in about six to eight weeks. ... RHP Hector Noesi, who will start Saturday's game for the White Sox, spent two years in the Seattle system, going 2-13 with a 5.79 ERA before he was traded him to Texas earlier this season. Noesi threw 6 2/3 scoreless innings in a 1-0 home win over the Mariners earlier this season. ... The game featured bandmates on opposite ends of the fan spectrum, as Pearl Jam guitarist Michael McCready sported Mariners apparel while playing the national anthem on his guitar, and lead singer Eddie Vedder came out of the Chicago clubhouse afterward wearing a White Sox hat. Both musicians live in Seattle, although Vedder spent a good part of his childhood in Chicago. … Former Mariners manager Lou Piniella will be honored before Saturday's game. Piniella met with reporters during a Friday luncheon, one day before being added to the Mariners' Hall of Fame in a pregame ceremony.