ST. PETERSBURG, Fla. — Jason Vargas isn't setting a season-long goal of allowing an average of one run a start. Yet that's where he is at after seven outings.

The major league ERA leader went seven more scoreless innings, Salvador Perez had a two-run double during a five-run eighth inning, and the Kansas City Royals beat the Tampa Bay Rays 6-0 on Thursday.

Vargas (5-1) allowed three hits and dropped his ERA from 1.19 to 1.01.

"It hasn't been done very often in this sport," Vargas said. "It's a nice thing to see when you're able to have good starts and put your team in a good position to have success at the end of the game."

It's the lowest ERA in the majors (at least 30 innings pitched) at the end of play on May 11th since Colorado's Ubaldo Jimenez (0.93) in 2010. The last AL pitcher to be this low was the Royals' Zack Greinke (0.51) in 2009.

Jorge Bonifacio hit an RBI single off Diego Moreno in the decisive eighth inning before Whit Merrifield had a run-scoring single and then circled the bases when centre fielder Kevin Kiermaier misplayed the hit for a three-base error.

Merrifield also homered for the Royals, who won three of four against the Rays. Kansas City had lost 13 of 16 entering the series.

Jake Odorizzi (2-2) gave up one run and four hits in six innings for the Rays. He had allowed three hits or fewer in each of his previous four starts.

Tampa Bay went 3-6 during a nine-game homestand against Miami, Toronto and the Royals. All three opponents are well under .500.

"We've got some guys that are having a rough time on offence, on defence, on the mound," Rays manager Kevin Cash said.

Merrifield put the Royals up 1-0 on a solo shot in the fourth.

Vargas made two nifty defensive plays during the fifth. He fielded Kiermaier's slow grounder down the first base line and tagged out the speedy outfielder, and also caught Derek Norris' liner.

Rays left fielder Corey Dickerson took a home run away from Eric Hosmer in the first by reaching over the short wall by the 315-foot mark near the line and catching the drive.

Kansas City centre fielder Alex Gordon took an extra-base hit away from Tim Beckham with a diving catch in the sixth. Gordon made his 932nd outfield start, but first in centre.

There was no carry over one day after Perez was hit by Chris Archer's pitch in the seventh inning of the Rays' 12-1 win Wednesday night. Perez felt Archer was throwing at him, while Archer said there was no intent.

TRAINER'S ROOM

Royals: CF Lorenzo Cain got a day off after playing three games on the artificial turf at Tropicana Field.

Rays: RF Steven Souza Jr. (sore right thumb) had a cortisone shot Wednesday and missed his third consecutive game.

GOLDEN STRUGGLES

Kiermaier, a Gold Glove winner, made three errors in the series, including one Monday night that allowed Cain to score after hitting a single.

"This has been a weird four days for me," Kiermaier said. "I never thought I'd be talking about my defence problems. I have to be better.

Kiermaier has four errors this year after making two in 2016.

"It just shows that they're human and things like that happen," Royals manager Ned Yost said. "It's a tough game, man."

WIFF CITY

Tampa Bay struck out seven times and remains on pace to set the team record for strikeouts in a season. The Rays have 374 in 37 games, an average of 10.11. The 2013 Houston Astros hold the record with 1,535, or 9.48 per game.

UP NEXT

Royals: LHP Danny Duffy (2-3) and Baltimore RHP Chris Tillman (1-0) are Friday night's starters as Kansas City opens a six-game homestand. Tillman, sidelined since March by right shoulder bursitis, went five scoreless innings against the Chicago White Sox in his season debut last Sunday.

Rays: RHP Alex Cobb (2-3) goes against Boston and reigning AL Cy Young Award winner Rick Porcello (2-4) Friday night at Fenway Park. The Red Sox right-hander had only four losses (22-4) all of last season.

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