SEATTLE — The series finale between the Seattle Mariners and Texas Rangers on Thursday night at Safeco Field was rather like watching a man stand on a tightrope pulled taut, our protagonist willing himself not to look down.

The last time Taijuan Walker stood out on the mound, he got just two outs and surrendered six runs. The Los Angeles Angels tagged the 24-year-old righty with back-to-back-to-back dingers last Saturday, knocking him out of the game before tardy fans even reached their seats.

It was a performance so brutal that when asked Thursday afternoon whether it would serve as a wake-up call for the young hurler, manager Scott Servais said “if that doesn’t do it, I don’t know what will.”

So yeah, when Walker walked the first two Rangers batters of the game, most of the 17,473 in attendance inwardly cringed.

Walker wobbled, but he never fell. The offense provided a helpful cushion, and the righty did just enough to earn his first win since June, Seattle holding on to a 6-3 win and the series victory on Thursday at Safeco.

Walker allowed three runs and seven hits in five innings, far from an economical start but a tough-minded one. Seattle (72-68) took three out of four from the American League West leaders and pulled within 4 1/2 games of the AL’s second wild-card berth.

After stranding two runners in the top of the first, Texas went down in order in the second before Walker worked himself into more danger in the third.

He plunked the nine-hole hitter, Robinson Chirinos. He came around to score on Ian Desmond’s single, but Mariners left fielder Guillermo Heredia did his pitcher a favor by later throwing out Desmond at the plate. Rougned Odor added another run with a two-out, RBI single, but Walker escaped with just two runs of damage.

The Mariners offense provided him with a cushion with a three-run fourth, reassurance were he to tumble.

Dae-Ho Lee had given the Mariners an early lead with a solo home run in the second, and the bats got to Rangers starter Derek Holland in earnest in the fourth. Kyle Seager singled, Lee walked and Martin also singled to load the bases. Chris Iannetta knocked in two runs with a double down the line and Heredia pitched in another with a dribbler up the middle.

Walker’s tightrope trembled again in the top of the fifth, when Desmond led off with a home run to cut the deficit to one. Adrian Beltre roped a single to left, necessitating a mound visit from pitching coach Mel Stottlemyre.

Walker, cowed after last Saturday’s outing, had approached Stottlemyre in its aftermath, still “in shock.” They went to work the next day, tinkering with mechanics, closing Walker’s stance and adding a higher leg kick.

“I know he has done a lot of work over the last three or four days with Mel, and opened himself up to some other ideas, which he hasn’t always been receptive to,” Servais said before the game. “Any player who lets his guard down and is receptive, I’m really rooting for them, because you want to see some kind of payback.

“No matter how it goes tonight, I think you’re going to see a different guy going forward.”

Odor then fired off a series of ominous foul balls, missiles that sent heads ducking. Walker got him eventually, with an off-speed pitch in the dirt. Mitch Moreland struck out, too, but again Walker had to dig deep, turning an 0-2 count into a full one before winning the battle with a 90-mph splitter.

It was the 10th pitch of the at-bat and Walker’s 105th-and-final pitch of the night.

Evan Scribner, Nick Vincent and Edwin Diaz followed out of the Seattle bullpen. Seager ripped a two-run homer — his career-high 27th of the season — to push the lead to 6-3 in the bottom of the seventh.

And Walker, at long last, had his hard-won fifth win of the season.