SEATTLE -- Wade LeBlanc made only one bad pitch in his six innings of work Sunday, but that was enough for the Rays to eke out a 1-0 victory at T-Mobile Park as the Mariners’ offensive woes continued.

Eric Sogard homered off an 86-mph fastball that LeBlanc left over the plate on a 3-2 pitch in the fourth for the only damage off the 35-year-old southpaw. But with Ryan Yarbrough holding the Mariners to three hits in 8 2/3 innings, the Rays picked up their first three-game series sweep in Seattle since 2010.

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“That one pitch decided the whole game,” said LeBlanc, who came in after opener Sam Tuivailala’s perfect first and allowed just the one run on five hits. “You’d like to say it doesn’t happen very often, but sometimes it does. Unfortunately we were on the wrong end.”

The Mariners had just four baserunners in the game, with none advancing past first base.

The Mariners have now lost eight of their last nine games while falling to a season-low 23 games under .500 at 48-71.

While Seattle ranked among the MLB leaders in home runs and runs in the early going, that theme has gradually faded since the trades of Edwin Encarnacion and Jay Bruce, the lingering injury absence of Mitch Haniger and recent cold spells from Domingo Santana and Daniel Vogelbach.

The Mariners have scored just 17 runs, hit six homers and batted .166 while going 1-7 in their first eight August games. The Rays are headed the other direction, having won 12 of 15 to move into position as the second American League Wild Card team at 69-50.

LeBlanc was much better than he was in his two previous outings, when he’d gone 0-2 with a 10.61 ERA. His trademark changeup was more effective, and he sailed through his six frames on 78 pitches with no walks and three strikeouts.

“It felt better,” he said. “The changeup was effective because pitching inside was effective. Not just inside, but inside for strikes. That’s huge. Unfortunately, I wasn’t able to execute one pitch and it cost us.”

Yarbrough, who was traded by the Mariners to the Rays prior to the 2017 season as part of a package for Drew Smyly, kept Seattle off balance throughout with his assortment of offspeed offerings.

“It’s a different slot, it’s a little funkiness, a little deception to it,” Mariners manager Scott Servais said. “You have to give him credit. He threw a ton of strikes. He threw his breaking ball and got that cutter over anytime he needed. And located really well. He pitched a heckuva ballgame.”

“He pitches,” said Mariners center fielder Mallex Smith, who was a teammate of Yarbrough’s with Tampa Bay before being dealt to Seattle last winter. “That works sometimes, and it got us tonight. He lives off deception and he did a really good job mixing everything up in every count. He was extremely effective, so kudos to him.”

The Mariners’ best chance off Yarbrough came in the seventh when first baseman Austin Nola ripped a 387-foot drive to right-center field, but former Mariners center fielder Guillermo Heredia made an outstanding play to haul it at the wall.

“Unbelievable play,” Servais said. “We’ve seen him do that before. He’s an outstanding outfielder, takes really good routes and he can finish plays. That’s not an easy ball, right up against the wall, when you know you’re going to hit it. I was hoping Austin had got just enough to get it over the fence because if it stays in the yard, Guillermo has a pretty good chance of getting it.”