Through his first five innings on Thursday night, Yusei Kikuchi looked like he had found the rebound he was looking for.

Kikuchi needed just 13 pitches to get through the first two innings, despite hitting a batter and giving up a single to Hunter Dozier in the second, then went on to put away the next 12 batters in order in the Mariners’ 6-4 loss to the Royals at T-Mobile Park.

• Box score

It was the making of a bounceback night for the lefty who had given up seven runs in 2 2/3 innings to the Astros in his last start. But Kikuchi’s turnaround came to a quick halt as he could not record an out in the sixth after loading the bases, and was replaced by Joe Smith who surrendered a go-ahead grand slam to Salvador Perez.

“[Kikuchi] was getting outs,” Mariners manager Scott Servais said. “But I saw the game changing and I tried to give Joe a chance to get us out of it. It just didn't happen tonight.”

Kikuchi allowed three straight hits to begin the sixth inning and gave up a run on a Whit Merrifield double. In the next at-bat Kikuchi walked Nicky Lopez on four pitches, which signaled the end of his night with 65 pitches (43 strikes).

Perez’s grand slam put the Mariners in their first deficit of the night after getting out to a 4-0 lead on a night when Kyle Seager and Jake Fraley homered. The slam left Kikuchi with four runs charged against him in the loss.

Servais said the end to Kikuchi’s night felt like it came in an instant.

“Yusei has struggled a little bit probably the last three or four outings coming into this one. It did get away from him there pretty quick,” Servais said. “A couple quick hits and then Merrifield bangs the first pitch down the corner. You look up and it's second and third and now we issue a walk [and the] bases are loaded and kind of the game is in the balance right there with their best hitter at the plate. It did happen very quickly”

Coming out of the All-Star break, Kikuchi has had some rough outings. He finished Thursday’s start with a 6.46 ERA in 39 innings across eight starts coming out of the break and has had just two quality starts in the second half.

Kikuchi said the effectiveness of his cutter, which he threw 33 times, was something he had not had in his recent starts, but his exit left him disappointed.

“I felt like I was under control for the first five innings there,” Kikuchi said through an interpreter. “Throwing a good amount of strikes, executing my pitches. But leaving all those runners on there in the sixth inning and not being able to finish my outing on a solid note is a little frustrating.”

Though Seattle has had a knack for making comebacks of late, the big hit didn’t come against the Royals after the Mariners’ lead disappeared following Kikuchi’s exit.

They loaded the bases in the first and fourth innings, but managed to score just one in those situations, on a bases-loaded walk by Fraley in the first.

The Mariners were 2-for-8 with runners in scoring position and left eight men on base.

“Kind of a different type of game for us tonight, that's for sure,” Servais said. “I thought we were in pretty good shape. But offensively tonight, I thought we had a lot of chances to put a lot more runs up there. It wasn't our night as far as situational hitting with the guy on third.

“It happens some nights, but you’ve got to take advantage of those situations when we had chances to put more runs up there. … It's something that we've been very good at this year and just weren't able to get it done tonight.”