Rox bottom has never looked or smelled worse.

Any optimism the Mets carried into the weekend after snapping a 12-game losing streak and winning two straight (before losing Friday) was completely siphoned over six hours on Sunday.

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Manager Carlos Mendoza’s beleaguered bunch managed only one run over 18 innings in getting swept by the hapless Rockies in a Citi Field doubleheader.

The three-game series sweep by Colorado was complete with the Mets’ 3-0 loss in the nightcap. The Mets fell 3-1 in the doubleheader’s first game.

The Mets are last in MLB, averaging 3.17 runs per game.

“I don’t think I have ever seen anything like this where it goes for so long, when you have got so many guys struggling at the same time,” Mendoza said of an offensive attack that has scored three runs or fewer in 14 of the last 17 games.  

With Monday’s off day, questions will continue to swirl about Mendoza’s job security. Mendoza isn’t the one swinging to weak contact at the plate – and wasn’t responsible for constructing this roster (that was president of baseball operations David Stearns’ undertaking) – but Mets owner Steve Cohen can’t fire the entire team.

“As players we have to perform – definitely this is not Mendy’s fault or David’s fault,” Juan Soto said. “We definitely put a great team together and we have to be the ones who gotta go out there and perform.”

Chase Dollander and his 100-mph heat provided resistance in the nightcap. It was quite the contrast to journeyman Jose Quintana’s assortment of junk in Game 1.

In the nightcap, Kodai Senga continued his freefall by lasting only 2 2/3 innings and allowing three earned runs on three hits with three walks. It was a third straight start in which the right-hander failed to complete even four innings.

What’s next for Senga? The bullpen and minor leagues are among the options. But Senga would have to give his consent for a demotion to the minors (he allowed it last September, when he finished the season at Triple-A Syracuse).

“That warrants a lot of discussions with a lot of different people,” Senga said through his interpreter.

He added: “I don’t know what’s going to come, but I know that my performance out on the field is something where I can be like, ‘Oh, I’m going to be in the rotation.’ I don’t know what’s going to happen.”     

Hunter Goodman’s two-run homer in the third that gave the Rockies a 3-0 lead suggested Senga might be facing short work. And after Senga walked two batters in the third inning, Mendoza removed him.

Carl Edwards Jr., in his Mets debut, gave the team a chance with 3 1/3 scoreless innings in relief. Edwards, who struck out five, walked three batters without allowing a hit.  

The Mets took a shot at a late rally in Game 1, but it fizzled in the eighth. After Soto walked to load the bases with one out, Luis Robert Jr. popped out and Mark Vientos struck out, eliciting boos from the crowd.

Nolan McLean was removed after five innings in which he allowed two runs, one unearned, on five hits and two walks with seven strikeouts. The start matched McLean’s shortest of the season; he also went only five innings against the Pirates in his initial outing.

Tyrone Taylor’s homer leading off the bottom of the fifth tied it 1-1. Quintana had retired 11 straight batters before Taylor cleared the fence in left-center for his second homer this season.

Vientos’ throwing error helped the Rockies score an unearned run in the sixth. Vientos, at first base, fielded Rumfield’s grounder and attempted a throw to second to nail Mickey Moniak. But the throw hit Moniak, leaving the bases loaded with nobody out. Huascar Brazoban replaced McLean and induced a double play grounder from Johnston, with the run scoring.

Brazoban surrendered an RBI single to Jake McCarthy in the seventh that widened the Mets’ deficit to 3-1.

McLean acknowledged the team’s frustration as the losses continue.

“We’re a bunch of highly competitive dudes and nobody enjoys losing and not going out there and performing the way we think we should,” McLean said. “I’m here early and I see a lot of guys putting in the work and grinding.”