"Obviously, I couldn't find the zone, walking just about everybody that got up there," a relieved Wilhelmsen said. "I got lucky on the guys that swung early and in a game like that, you've just got to buckle down and keep fighting. We can't lose that game."
The Mariners have lost plenty of those in the past, going 4-24 against the White Sox over the previous three years and 3-19 at U.S. Cellular dating back to 2009.
But in a game that began with the temperature at 34 -- equaling the coldest start for a Mariners game since 1988 -- Seattle pulled this one out with two runs in the top of the 10th and then the hang-on finish.
"We couldn't go any further and still win the ballgame there," manager Eric Wedge said of Wilhelmsen's wild finish. "He just bowed his neck. That's why he's our closer, because he's tough. He didn't give in to it. He didn't tighten up. You still saw the ball jumping out of his hand, you saw a good breaking ball.
"He got a little off line there and started pulling the fastball, but he worked his way back into it. He made it tough on himself, but in the end he got it done."
The Mariners had already blown a 6-1 lead when starter Blake Beavan unraveled in the fifth, so they were glad to escape with a series-opening victory that puts them at 3-2 on the early season.
The offense did its part with six extra-base hits in a 12-hit night, none bigger than Kendrys Morales' double in the 10th that pushed Franklin Gutierrez across with the go-ahead run. Jesus Montero followed with an RBI single and the Mariners seemed ready to add another, but Montero was thrown out at the plate trying to score on a double by Kyle Seager.
Beavan couldn't hold the initial 6-1 lead, giving up four runs in the fifth as a promising season debut quickly dissolved to a final line of five runs on six hits in five innings.
The big right-hander said he tried switching things up with more offspeed offerings in the fifth, but should have stuck with what had been working.
"I just wasn't executing pitches with my offspeed, and my fastball obviously should have been a better weapon for me to use, but I didn't utilize it enough when I needed it," said the 24-year-old. "I just need to learn from it. The main thing is we got a win. We kept it right there and these guys stepped up and got a couple runs late in the game for us."
Beavan said the cold weather was difficult as well as the game wore on, a statement that will get no disagreement from the hometown White Sox.
"The good part about tonight is it's over, basically," said White Sox designated hitter Adam Dunn. "It was miserable out there for everybody."
One player who thrived despite the chill was Gutierrez, who homered to right field leading off the game en route to a 3-for-5 night with three runs and three RBIs.
It was Gutierrez's second leadoff home run in the past three games. He totaled five home runs over the previous two injury-plagued seasons, but is off to a nice start this season with hits in all five games and a .412 batting average with six RBIs.
The Mariners got five of their runs on six hits in a fifth-inning rally before White Sox starter Jose Quintana could get an out. That burst included a two-run double by Gutierrez, a run-scoring triple by Michael Saunders, a double by Jason Bay for his first hit as a Mariner and RBI singles by Brendan Ryan and Morales.
But the White Sox responded with four runs in the bottom of the fifth off Beavan, including a two-run homer by Alejandro De Aza and a solo shot by Alex Rios, then tied the game at 6 in the seventh after Wedge went to his bullpen.
Four different relievers held the White Sox to one run over the final four frames before Wilhelmsen strode to the mound and made things interesting in the 10th.
But after three walks and a single cut the lead to one and loaded the bases, the lanky right-hander froze Flowers with a first-pitch curve and then struck him out with a pair of 95-mph fastballs.
"I felt real lucky with that curveball there," Wilhelmsen said. "I thought it was a strike, but I threw some curveballs today that were in the other batter's box. I don't know. It was just bear-down time of the utmost importance.
"It was just one of those days. Some days it's just not there. We were able to figure it out and get three outs."