CINCINNATI (AP) — The Reds are starting to wonder when it will all end.

The defending NL Central champions fell to a new season low with an 8-2 loss to the New York Mets on Wednesday night, one that felt a lot like so many of them lately.

The Reds had another rough time in the field — their fourth error in two games, plus a passed ball that set up a run. In the end, they were four games under .500 (50-54) for the first time this season.

“Something’s going on,” Bronson Arroyo said. “Things just aren’t going our way.

“It’s totally frustrating. We haven’t had any long winning streaks. It seems like it’s getting harder and harder to be optimistic.”

The Mets have won the first three games of the series despite parting with their most productive hitter. All-Star outfielder Carlos Beltran accepted a trade to the Giants shortly before the game, then went into the clubhouse to say goodbye to teammates.

Beltran was headed to Philadelphia to join the Giants for a game on Thursday night. His fill-in helped the Mets get a win anyway.

Rookie Lucas Duda homered off Arroyo (7-9), who couldn’t extend his long run of success against the Mets. David Wright also homered and drove in four runs. Daniel Murphy had a career-high four hits.

“I don’t know if they’re pressing,” Reds manager Dusty Baker said. “They’re hitting the ball hard on us, real hard, especially Murphy and Wright tonight. We weren’t fooling them too much. They beat us pretty good.”

Mike Pelfrey (6-9) gave up seven hits in his second complete game this season, including Joey Votto’s second homer of the series.

The Mets moved two games over .500 even as they said goodbye to a popular player. Duda — the club’s minor league player of the year in 2010 — let it sink in that he could be playing a lot more in an unaccustomed position. He’s more familiar with left field and first base.

“I’ll try my best out there and see what happens,” he said.

Mets manager Terry Collins didn’t hesitate to plug him into Beltran’s spot in right.

“He’d better get comfortable real fast,” Collins said.

Didn’t take long.

Duda opened the sixth inning with his second homer of the season off Arroyo, who has given up 30 overall, the most in the majors. It’s a bad sign for the Reds when Arroyo can’t beat the Mets. The right-hander was 7-1 in his previous 10 starts against New York, and was 5-0 in his last six outings against the Mets, allowing a total of 13 runs.

This time, he lasted six innings and gave up five runs.

“Winning heals all that, but we’re struggling right now, no doubt about it,” Arroyo said.

New York blew it open with Wright’s three-run homer in the seventh off Jose Arredondo, making it 8-1. Wright has been on a hitting tear since he returned from a stress fracture in his lower back, going 12 for 28 with two homers and 11 RBIs in six games. He also had a sacrifice fly off Arroyo.

Pelfrey gave up Votto’s solo homer in the fourth and Chris Heisey’s sacrifice fly in the seventh.

Notes: The teams conclude their series Thursday afternoon. They play again at Citi Field from Sept. 26-28. … The Mets haven’t swept a series in Cincinnati since 2003, when they took three games during Great American Ball Park’s inaugural season. … Beltran should be back in Cincinnati soon. San Francisco opens a weekend series at Great American Ball Park on Friday. … Arroyo’s 30 homers allowed are one shy of his career high. He gave up 31 in 2006 and 2009, both with Cincinnati. … Votto is 5 for 14 with three homers career off Pelfrey.