Miguel Olivo finished a single shy of the 3, in the second test of a four-game series.
Blake Beavan (4-5) gave up three runs on nine hits over 6 1/3 innings to pick up his first win since August 6.
Alex Gordon hit a solo homer and drove in two runs for the Royals, who have lost three in a row.
Jeff Francis (5-16) allowed five runs on nine hits over 3 1/3 innings to take the loss.
"I was just missing locations over and over again and when I needed to make a pitch I couldn't make it," Francis said.
Gordon led off the game with a homer to right. Melky Cabrera followed with a triple and scored on Billy Butler's groundout for a quick 2-0 Kansas City lead.
The Mariners tied the game in the home first. Brendan Ryan grounded into a fielder's choice, moved to second on a wild pitch and crossed the plate on Olivo's ground-rule double to left. Justin Smoak knocked in Olivo with a base hit up the middle.
Seattle hit two homers in the third to take the lead for good. Suzuki led off with a blast to right. Two batters later, right fielder Jeff Francoeur jumped, then reached over the wall to take a homer away from Dustin Ackley. Olivo cleared the wall in left with two outs for a 4-2 lead.
The Mariners added a run in the fourth. Alex Liddi doubled to left and scored on Suzuki's single. Nathan Adcock took over on the mound and recorded the final two outs of the frame to keep it a 5-2 contest.
The home team tacked on two more runs in the fifth. Olivo tripled and crossed the plate on Smoak's single. Wily Mo Pena's double knocked in Smoak for a 7-2 lead.
The Royals got one run back in the seventh. Alcides Escobar tripled with one out and scored on Gordon's infield single. Shawn Kelley took over for Beavan and recorded the final two outs of the inning to keep it a 7-3 game.
"I knew if I hit a single I would hit for the cycle. I just tried to put the ball in play, but it didn't happen for some reason," said Olivo, who grounded into a double play to end the eighth.
Kelley went on to pitch a scoreless eighth and Jamey Wright held the Royals off the board in the ninth.
Seattle is 31-19 against the Royals at Safeco Field, which opened in 1999 -- its second-best winning percentage against an opponent there...The Royals went 1-for-6 with runners in scoring position and stranded eight...Adcock was charged with two runs on four hits over 2 2/3 innings.