ST. PETERSBURG, Fla. (AP) -- Tampa Bay reached its high-water mark of 2018 by just putting the ball in play.
A throwing error on Kevin Kiermaier's bases-loaded grounder in the bottom of the ninth inning helped the Rays complete their first season sweep of an American League opponent with a 4-3 victory over the Kansas City Royals on Thursday night.
"A win is a win," Kiermaier said. "We'll take it any way possible."
Tampa Bay swept the four-game series and finished 7-0 against the lowly Royals this year. The only other season sweep in team history that included multiple series was a four-game wipeout of the Marlins in 2013.
Jake Bauers drew a leadoff walk from Brian Flynn (4-4) in the ninth and went to third on C.J. Cron's single.
After Joey Wendle grounded out and Willy Adames was intentionally walked to load the bases, Kiermaier grounded a 3-2 pitch to first baseman Ryan O'Hearn, who made a wild toss to the plate.
"We always say, `Put the pressure on the defense,"' Kiermaier explained. "Anytime you put the ball in play, you at least give yourself a chance."
Sergio Romo (3-3) worked a perfect ninth and the Rays improved to a season-high six games over .500 (67-61) with their fifth consecutive victory. It is Tampa Bay's sixth winning streak of at least five games this year.
Kansas City, which has lost five in a row and 17 of 21, fell a franchise-record 52 games under .500 at 38-90 and was eliminated from the playoff race.
"We wanted to salvage one at the end of the series," Flynn said. "You don't want to be the guy that comes in here and gives that one up."
The Rays tied it at 3 when Matt Duffy scored from second on bad throw to first by second baseman Whit Merrifield on a potential double-play grounder hit by Cron.
Tampa Bay appeared to go up 4-3 later in the seventh on Kiermaier's grounder, but the run was taken away after a replay review determined Adames made an illegal slide at second base. The call was changed to an inning-ending double play.
"There were a lot of odd things that took place in that game," Rays manager Kevin Cash said.
Alex Gordon had an RBI single in a two-run fifth against Tampa Bay starter Tyler Glasnow that put the Royals ahead 3-2.
Adames hit a run-scoring infield single against Danny Duffy during a two-run third.
Duffy, making his first start in 12 days due to a left shoulder injury, allowed two runs and six hits over five innings.
"The last start I felt really bad," Duffy said. "This start I felt really good."
Lucas Duda drove in a run with a first-inning single and had a potential two-run extra-base hit taken away with two outs in the third on a leaping catch by Rays right fielder Carlos Gomez.
Glasnow allowed three runs, five hits and three walks in five innings. He struck out eight.
Royals: INF Adalberto Mondesi (hamstring) was out of the lineup. ... RHP Ian Kennedy (left oblique) will throw a simulated game Friday. ... OF Jorge Bonifacio (lower back stiffness) missed his third straight game.
Rays: OF Tommy Pham (dislocated right ring finger) felt soreness hitting off a tee but could play this weekend.
Former Royals George Brett, Mike Sweeney, Bret Saberhagan and Reggie Sanders will visit U.S. troops at four locations in the Middle East next month as part of a USO trip. The group will watch a Sept. 11 telecast with members of the Missouri National Guard's 35th Combat Aviation Brigade.
Merrifield had three hits, extending his hitting streak to 12 games. ... Rays LF Mallex Smith went 3 for 5 and has multiple hits in seven of his last eight games. ... The Royals have been swept 15 times this season. . Tampa Bay has played 52 one-run games, most in the majors. The Rays are 24-28 in those games.
Royals: RHP Brad Keller (6-5) will face Cleveland RHP Mike Clevinger (9-7) on Friday night.
Rays: Will go with a bullpen day, including LHP Jalen Beeks (2-1), against Boston RHP Hector Velazquez (7-1) on Friday night.