DENVER — Craig Kimbrel didn’t record an out until he faced his fifth batter Thursday, by which time the Mets’ sweep dreams had been mostly obliterated.

Offensively, the Mets sputtered following a recent uptick, but the afternoon went haywire in the eighth inning when Kimbrel entered a tie game against the Rockies and loaded the bases with nobody out. Jake McCarthy smashed the second pitch for a grand slam, sending the Mets to a 6-2 loss at Coors Field that snapped their three-game winning streak.

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Kimbrel, chosen to pitch the eighth a day after the Mets used much of their bullpen and then went heavy on relief following a short Christian Scott start, threw a 94-mph fastball that McCarthy hooked around the right field foul pole — the home run call stood on replay — leaving the Mets feeling Rocky Mountain low.

“There is not really an angle there where you can tell if it’s fair or foul,” manager Carlos Mendoza said. “And it didn’t go our way there.”

Luke Weaver, who pitched an inning the previous night, is Mendoza’s preferred choice in the eighth inning but was unavailable. That left the job to the 37-year-old Kimbrel, who previously had given the Mets three straight scoreless appearances.

“We had to use a lot of our guys [Wednesday], and some of them weren’t available today,” Mendoza said. “I am not going to blame that on them. We had chances today.”

The Mets fell to 4-2 on the road trip and will begin a three-game series Friday at Arizona.

Kimbrel allowed singles to TJ Rumfield and Troy Johnston to begin the winning rally before walking Willi Castro to load the bases. McCarthy jumped on the second pitch.

“On the home run pitch, it was location; I was trying to go up and I aimed it down,” Kimbrel said.

At the plate, the Mets went 1-for-9 with runners in scoring position.

Scott was removed at 82 pitches before he could face the Rockies a third time through the order. The right-hander allowed one earned run on three hits and two walks over 4 ²/₃ innings with six strikeouts. Scott, returning from a missed season rehabbing from Tommy John surgery, will be handled with care, according to Mendoza.

“We had a number of pitches in mind, and he pretty much went over that number of pitches,” Mendoza said. “He did his part. We just couldn’t close it out.”

It was Scott’s second start of this road trip in which he kept the Mets in the game. Last week, he held the Angels to three earned runs over five innings before the Mets rallied for the victory.

“[The Rockies] did a good job of making me work the second time through the order,” Scott said. “I would have liked to work deeper into the game, but they did a good job of making me battle there.”

The Mets jumped on Jose Quintana for two runs in the second to take a 2-0 lead. Andy Ibáñez drove in the first run with a sacrifice fly and Tyrone Taylor’s RBI single extended the lead. Austin Slater’s leadoff single and Marcus Semien’s ensuing walk started the rally, with the runners advancing to second and third on a wild pitch.

Juan Soto’s one-out triple in the third was wasted when Mark Vientos, following a walk to Bo Bichette, grounded into an inning-ending double play.

Scott sailed into the fourth before allowing an RBI single to Castro that trimmed the Mets’ lead to 2-1. Tyler Freeman bunted for a single and Johnston walked before Castro delivered. But with runners on the corners, Scott struck out McCarthy to avoid further damage.

Huascar Brazobán got the final out in the fifth after Scott walked Edouard Julien and was removed. Brazobán surrendered a bloop RBI double to McCarthy in the sixth that tied it 2-2. Austin Warren walked Kyle Karros to load the bases before striking out Brett Sullivan to end the inning.

Soto batted with runners on first and second in the seventh, following walks to Francisco Alvarez and Vidal Brujan, but popped up for the final out.

“You are always trying to get [the sweep],” Mendoza said. “But then you look back and say, ‘OK, we won the series, move on to the next one.’ That is the bottom line. We have got to continue to win series.”