SEATTLE -- One swing was all it took, to change a game, a series and possibly a whole lot more for Nelson Velázquez.

When Velázquez came to the plate in the top of the seventh inning, it had been 101 at-bats since his last home run on April 4 against the White Sox. In the five weeks since, Velázquez was slashing .214/.280/.276, with 33 strikeouts to just 21 hits.

Tuesday at T-Mobile Park didn’t start much better, with a pair of strikeouts giving him 10 in his first 20 plate appearances on the Royals’ current road trip.

Then Logan Gilbert leaked a 1-0 slider over the plate. Velázquez changed his fortunes in a heartbeat, launching a three-run shot out to left field, and the Royals had all the scoring they’d need in what turned out to be a 4-2 win over the Mariners.

“That’s clearly the biggest spot in the game offensively,” Royals manager Matt Quatraro said. “He’s been scuffling a little bit. This trip, he’s got it going a little bit, but that was a big hit for him, personally and for the team.”

It was the third home run of the season for Velázquez, who hit 14 in 40 games in 2023 after coming to the Royals from the Cubs at the Trade Deadline. Coming into Tuesday, Velázquez’s .226 batting average through 36 games was only a shade below his post-trade clip, but his slugging percentage was down 240 points -- from .579 to .339 -- due to the lack of home runs.

“Baseball is about ups and downs,” Velázquez said. “It’s not an easy game. The hardest thing in this game is hitting. But I just tried to stay positive and go to home plate and do all I can to help the team, and today was the day, and I’m happy for it.”

Gilbert had faced the minimum through five innings despite allowing a pair of hits and a walk, thanks to a pair of double plays and an assist from the outfield when Hunter Renfroe tried to stretch a single into a double.

Velázquez hadn’t fared much better than the rest of the lineup in his first two at-bats. In the second, Gilbert took him through the wringer with six straight offspeed pitches -- including four sliders -- before blowing a 3-2 fastball by him. In the fifth, Velázquez saw four distinct pitches in a row, striking out on a splitter.

Despite seeing a bit of everything his first two times up, Velázquez went up for his third at-bat -- after Bobby Witt Jr. and Salvador Perez set the table with walks -- looking for one thing and one thing only.

“He’s a high-percentage slider guy, so I went there with a plan in that at-bat, just to look for the slider and trying to hit the ball to the middle,” he said. “I stuck with my plan, and good things happened.”

Velázquez got two sliders in a row and didn’t miss the second, with the go-ahead shot leaving his bat at 107.8 mph -- his fourth-highest exit velocity of the season.

That one swing was enough, in large part, thanks to the pitching effort the Royals got on the flip side. Michael Wacha posted his best outing in five weeks with six innings of one-run ball, striking out seven and allowing just three hits and two walks. Luke Raley tagged him for a home run on a hanging curveball to put the Mariners ahead in the bottom of the fourth inning, but Wacha finished his night by retiring seven of the last eight batters he faced.

“His stuff was good today,” Quatraro said. “The slider was better, he’s been working on that. His velo was up early, he got the ball up the zone when he needed to, he got the ball down and his changeup was good like usual.”

The win was Kansas City’s first in Seattle since Aug. 28, 2021, snapping an eight-game skid in the Pacific Northwest. And it was their 10th comeback win already this season, pulling their series in the Emerald City even.

“We stay together for the 27 outs, no matter what," Velázquez said. “We’re not being selfish in any moment, so in any time it can happen, no matter if we’re losing by three, five, seven. Any time, we can come back, because right now, we’re together the whole time. We’re in a great moment right now.”