Updated

Jason Vargas pitched eight strong innings of one-hit, one-run ball and the Seattle Mariners downed the Kansas City Royals, 4-1, in the opener of a four-game set Thursday at Safeco Field.

Vargas (11-7) struck out five and walked three with the only blemish coming on a two-out double from Billy Butler. Vargas, who has been at the center of trade rumors with the deadline approaching, has now won his last four starts and hasn't taken a loss since June 20 against the Arizona Diamondbacks.

"Jason Vargas has been as consistent as anybody this year. (He) did a great job," said Mariners manager Eric Wedge of his starter. "He has a great heartbeat out there and all that plays into his success."

Tom Wilhelmsen fired a scoreless ninth to nail down his 12th save of the season, while Mike Carp registered three hits and plated a pair for the Mariners, who have won two of their last three contests.

Luis Mendoza (4-7) suffered the loss after giving up all four runs on nine hits and three walks over five-plus innings of work.

Butler finished with a pair of doubles to account for the only two Royals hits as they lost for the fourth time in their last five games.

"We just couldn't get anything going, we couldn't do anything off him," said Royals manager Ned Yost of Vargas. "He pitched a great game."

Dustin Ackley got things going with a single to start the first inning, and Casper Wells followed two batters later with a base hit of his own.

John Jaso then lifted a fly ball into right field, but Jeff Francoeur misplayed the ball as it dropped in front of him. He alertly threw to second to catch Wells for the force out, but Mendoza drilled Kyle Seager to load the bases.

Carp then followed with a ground ball up the middle to score Ackley and Jaso for the early 2-0 lead.

Vargas mowed through the Kansas City lineup the first time around before Lorenzo Cain worked a two-out walk in the fourth.

Butler followed with his 200th career double to give the Royals their first hit and plate their only run, as Kansas City would remain hitless the rest of the way until Butler added a two-out double in the ninth.

Brendan Ryan smacked a one-out single to score Carp in the fourth, while Miguel Olivo and Carlos Peguero stroked back-to-back doubles to start the sixth, with Peguero's plating Olivo to account for the final margin.

Game Notes

Seattle took three of four from the Royals in Kansas City from July 16-19...Vargas has pitched at least six innings in 19 of his 22 starts this season. He is now 4-1 in five starts against the Royals...Kansas City went 0-for-2 with runners in scoring position and left four on base.