"It just gives you confidence going into the season, knowing that everybody's ready, everybody's playing well, and it gives you a good feeling about starting the season," manager Ned Yost said.
Franklin Gutierrez and Michael Morse hit solo home runs in the seventh against Royals left-hander Tim Collins to continue the Mariners' long-ball exploits. Morse cleared the 40-foot-high batter's eye atop the 410-foot fence in center field with a mammoth shot, his seventh of the spring.
Gutierrez led off the seventh with a bolt to right field, his fifth of the spring. The Mariners have now homered in 29 of their 30 games and lead all Major League teams this spring with their club-record 54 long balls.
Right-hander Sugar Ray Marimon, a Minor Leaguer who was in Royals camp earlier this spring, got the late start for Kansas City after the decision was made to move Bruce Chen to the bullpen. Marimon, 24, gave up four runs and seven hits in 4 1/3 innings before turning a 7-4 lead over to the Royals relievers.
Bonderman, attempting to come back from arm and shoulder problems that have sidelined him since 2010, pitched four strong innings before getting roughed up in his final spring start.
Bonderman hit 90-93 mph with his fastball in the early going and held the Royals to one run and three hits in the first four frames. But he was touched for a triple and three doubles in the six-run fifth, though the final two-run double came on a drive by Jeff Francoeur that left fielder Morse seemed to lose at the last second at the wall in left center.
"I was definitely tired," Bonderman said after his longest outing this spring. "I had some fatigue, and it wasn't the best stuff I've had. It definitely wasn't what I was hoping for. I was rolling along pretty good, and then I got smacked in the mouth."
Hayes had an RBI triple in that rally, while Jarrod Dyson and Alcides Escobar doubled and scored as well.
Bonderman was sent back out for the sixth, but his velocity dipped to the mid-80s by that time, and he was relieved after a one-out single. His final line was 11 hits and seven runs with a walk and two strikeouts in 5 1/3 innings. Bonderman threw 89 pitches, and his spring ERA stands at 8.80.
The Mariners scored three on Marimon in the third with a two-run double by Gutierrez and a sacrifice fly by Kyle Seager, then tacked on another in the fourth on a double by Raul Ibanez and RBI single by Dustin Ackley.
Chen pitched the sixth for the Royals and loaded the bases with one out before getting out of the jam unscathed.
Lorenzo Cain was 2-for-4 with a double for the Royals, raising his spring average to .442. Morse finished 3-for-4 to raise his spring average to .353 for Seattle.
Up next: The last of three day-night, split-squad doubleheaders will occupy the Royals on Wednesday. The daytime squad, with newly anointed No. 5 starter Luis Mendoza pitching, will go to Maryvale Stadium for a 3:05 p.m. CT game against the Brewers, available for free in an exclusive webcast. Luke Hochevar is on the relief corps along with three candidates for the last bullpen job, Dan Wheeler, J.C. Gutierrez and Francisley Bueno. The nightside, with Opening Day starter James Shields on the mound, will meet the Cubs at 8:05 p.m. CT at Surprise Stadium. The second game will be on TV via FOX Sports Kansas City and available in a free webcast.