So much for starting the easy part of the schedule.

After taking two of three from the team with the best record in baseball, the Mets dropped two of three against the team with the worst record in baseball.

This series finished with back-to-back losses to the lowly Nationals, including a 7-1 defeat on Sunday afternoon at Citi Field in another quiet game for the Mets’ offense.

The three games against the Nationals (47-87) began a stretch of 16 straight games — and 24 of 30 to finish the season — against teams with sub-.500 records. But the Mets (85-50) could not take advantage this weekend or carry over any momentum from their midweek series win against the Dodgers, allowing their NL East lead to be cut to one game by the Braves — the smallest it has been since July 23.

“You just put it behind you,” said Jeff McNeil, who had two of the Mets’ six hits and drove in their only run, but also made a costly error at second base. “They took advantage of some mistakes and that’s what we’ve done all year to other teams. They played pretty good baseball this week. So good for them and we’ll move on.”

Carlos Carrasco’s first start back from the injured list did not last long, with the veteran giving up five runs (only one earned, thanks to McNeil’s error) over 2 ²/₃ innings.

Of greater concern, though, was the offense. A day after Patrick Corbin (6.28 ERA) held the Mets to one run on three hits over seven innings, Erick Fedde (5.08 ERA) limited them to one run on four hits over six innings.

It continued an inconsistent stretch for the Mets’ lineup, which has averaged just three runs per game over its last 12 games while going 6-6.

Asked whether he credited Corbin and Fedde versus the Mets’ offensive funk, Buck Showalter replied, “yes.”

“These are major league pitchers,” the manager said. “If you go off of the season as a whole, ours and theirs, you could make both of those points, probably more of the latter. But I’m always going to give credit to major league pitchers. We just haven’t scored runs in an area of need.”

The Nationals had something to do with that on Sunday, as Victor Robles leapt at the center-field wall to rob Francisco Lindor of extra bases in the third inning and second baseman Luis Garcia made a leaping catch to take a hit away from Daniel Vogelbach in the fourth.

But then there was the seventh inning, when the Mets put their first two batters on base before Eduardo Escobar hit a fly ball to left field. Cesar Hernandez had it in his glove before it popped out, but he threw to third base to get McNeil on the force out. Mark Canha had also retreated to first base, with McNeil appearing to signal for him to stay there, allowing the Nationals to throw to second base to complete the double play.

“It’s just a play where the defense gets rewarded for a bad play,” Showalter said. “It’s one of those plays that’s nobody’s fault, other than the left fielder’s.”

After the Nationals took a 1-0 lead in the first inning off Carrasco, the Mets tied it in the second on McNeil’s sacrifice fly. They went on to put runners on the corners with two outs before Tomas Nido grounded out to end the threat. It was one of only two innings all day in which the Mets had multiple base runners.

The tie didn’t last long, though, as the Nationals knocked Carrasco out of the game with a four-run third inning, with some help from McNeil’s error. The second baseman made a nice backhanded stop on a ground ball up the middle but bobbled the ball on the transfer from his glove, costing him at least the out at second if not a double play while the game was still tied.

“I just missed it,” McNeil said. “Just one of those plays. Didn’t make the transfer and it ended up being big.”