KANSAS CITY, Mo. -- Daniel Mengden's closest friends provided him with a nice cushion to break back into the win column.

Joey Wendle had a career-best four-hit game and scored three runs, while Mengden pitched seven scoreless innings as the Oakland Athletics crushed the Kansas City Royals 14-5 on Thursday night to complete a four-game sweep.

The A's 16-hit attack included three-run homers by Marcus Semien in the eighth and Ryon Healy in the third, and a two-run blast by Stephen Vogt, who matched his career high with five RBIs -- the third time he has accomplished that. Five A's had multi-hit games, led by Wendle's four singles.

"It's awesome," Mengden said of the run support. "You feel almost totally relaxed. We got out to a seven or eight run lead (actually nine after four innings). It's not saying a guaranteed win, but if I do what I'm supposed to do it's going to be a good day."

It was not only a good day, but a great series.

"We played well in all facets," A's manager Bob Melvin said. "We really played well. We got some leads and kept adding on. We got good pitching. We did everything as right this series as we did all year."

Mengden (2-7) gave up three hits, walked none and struck out six, picking up his first victory since June 27. He threw 88 pitches, 61 for strikes.

Edinson Volquez (10-11) took the loss, his first since Aug. 3, yielded nine runs (eight earned), seven hits and four walks in 3 1/3 innings.

The Royals scored all their runs in the ninth, which included Christian Colon's first career home run in his 293rd career at-bat, a three-run shot off Dillon Overton. The inning also included Hunter Dozier's double, his first career hit.

"A big monkey off my back, for sure," Colon said. "Hopefully there's many more."

After a scoreless first inning, Healy and Semien hit back-to-back doubles after two out in the second inning to produce the first A's run. That began an offensive avalanche as the A's would score eight more runs in the next two innings and chase Volquez.

Vogt hit a two-run double in a five-run third. Healy's moonshot, which cleared the left-field fountains and Statcast estimated at 480 feet, made it 6-0. Khris Davis and Yonder Alonso were aboard when Healy crushed a 2-2 Volquez changeup.

In the fourth, Volquez walked Vogt with the bases loaded and Davis drilled a two-run double to finish Volquez's evening after 81 pitches.

"He just struggled again tonight," Royals manager Ned Yost said of Volquez. "It's more mechanics than anything, because he had some really good changeups and he was on top, but he would get under them and left them up, and those are the pitches they did damage on."

With the Royals down 9-0 after five innings, that was manager Ned Yost's cue to bring in the subs. He removed catcher Salvador Perez, left fielder Alex Gordon, shortstop Alcides Escobar and first baseman Eric Hosmer, replacing them with Tony Cruz, Dozier, Raul Mondesi and Daniel Nava.

Vogt belted a two-run blast in the sixth inning for his 12th of the season while Semien delivered a three-run shot in the eighth for his 25th.

NOTES: Royals LHP Jason Vargas, who had Tommy John surgery in late July 2015, will make his first start Saturday against the White Sox. Vargas will be on a three inning, 45-pitch limit. ... The A's recalled LHP Dillon Overton from Triple-A Nashville. While he started five games for Oakland in his first three big league stints this season and 20 games with the Sounds, he will be used in long relief. ... Royals manager Ned Yost said OF Lorenzo Cain, who has not played since Friday because of left wrist inflammation, is "not making great progress," rendering it questionable he will return this year." ... A's RHP Henderson Alvarez will have arthroscopic shoulder Tuesday, performed by Dr. James Andrews. Alvarez, who had shoulder surgery last year while with the Marlins, has not pitched this year. ... A's RHP Kendall Graveman starts Friday at Texas. The Rangers counter with LHP Cole Hamels. ... The Royals continue their homestand Friday with RHP Ian Kennedy facing the White Sox, who will start All-Star LHP Chris Sale.