CHICAGO — The winning run was scored in the ninth in walkoff fashion, but the Mariners lost the game in the seventh inning when a three-run lead was squandered and tossed away like lint found inside a pocket.

With one out in the ninth, Todd Frazier’s ground ball down the left-field line off Nick Vincent scored Adam Eaton from second for the winning run in the White Sox’s 7-6 victory over the Mariners on Thursday night. Seattle drops to 67-60 and has lost three in a row for the first time since before the All-Star break.

Frazier had faced Vincent four times in his career, striking out all four times. But he pulled 2-1 fastball down the line just past Shawn O’Malley at third base. Eaton, who had blooped a leadoff single to center and moved to second on a sacrifice bunt, scored without a throw home.

That it got to that point in the game — tied in the bottom of the ninth with Vincent pitching with minimal margin of error — was a product of the miscues and lack of execution two innings before.

With James Paxton pitching just five innings in his return from the disabled list and the Mariners having a six-man bullpen, manager Scott Servais planned it out. He would try and go inning-by-inning — one pitcher each. His offense had given him some cushion, scoring three runs in the top of the sixth to break a 3-3 tie.

“We knew we were going to be stretched and have to use three or four guys to lock it down,” Servais said. “It just didn’t work out that way.”

Tom Wilhelmsen, who hadn’t pitched in three days because of minor back issues, pitched a 1-2-3 sixth.

An error from Ketel Marte and nonexistent command from Arquimedes Caminero made it all disappear in the seventh. A routine ground ball from leadoff hitter J.B. Shuck was booted by Marte to start the issues.

“I was in the right position, but the ball came up on me,” Marte said.

Caminero got some help from left fielder Nori Aoki, who made his second diving catch of the game to rob a single from Tyler Saladino. It was negated with a walk to Eaton and a double from Tim Anderson on a rocket to center that bounced over the wall to score a run.

Servais had no choice but to go to sidearmer Steve Cishek, who was supposed to pitch the eighth, to quell the rally. In the unenviable position of runners on second and third with one out, Cishek notched the strikeout he needed — getting Jose Abreu to chase a wayward slider for a swinging strike three.

But the Mariners’ former closer couldn’t close out the inning without further damage. Cishek fell behind 2-0 to Frazier and appeared to be working around him with first base open, opting for a slider away. But the pitch didn’t get far enough outside and Frazier yanked it into left field for a two-run single to tie the game.

“It was lined up and then we have the error and the walk and those things will bite you,” Servais said. “You give teams more than three outs in an inning, it will usually come back to get you, and it did tonight.”

Making his first major-league start since taking a line drive off his elbow on Aug. 7, Paxton looked a little rusty with his fastball leaking over the plate early in the game. He gave up three runs in the first inning on five hits.

“I was missing middle a little bit and they found some holes,” he said. “They were just ambushing the fastball, and I didn’t have a great feel.”

When Paxton finally got Shuck to ground out, eight batters had come to the plate and he’d thrown 31 pitches. There were a few hard-hit balls but more well-placed ground balls.

“That’s baseball,” he said. “But I was also missing my spots.”

He allowed just one base runner from the third to fifth innings.