Scott Diamond, the Twins’ most accomplished starter from a year ago, was back on the mound Saturday. He was healthy, stretched out and ready to pick up right where he left off from last season.

“My issue coming into the game was getting that rhythm,” Diamond said.

Mets leadoff hitter Collin Cowgill dug in at the plate. Diamond rocked and fired … and skipped his first pitch of the season to catcher Ryan Doumit.

“It was probably not there on the first pitch,” Diamond said with a chuckle.

It probably wasn’t there on his last pitch, either, an 0-2 curveball to Daniel Murphy in the fifth that was hit for an RBI single — the sixth of seven consecutive hits in the inning, and a hit that sent Diamond to the showers.

The Twins were on their way to their fifth loss in a row, 4-2 to the Mets, who were led by young righthander Matt Harvey’s brilliance.

It looks like a downer for Diamond, who underwent surgery a remove a bone chip from his elbow in December. He then tried to fast-track himself to be ready by Opening Day, only for common sense to win out at the end.

But there were glimpses in Diamond’s outing that suggested that he can take off from where he left off last season, when he went 12-9 with a 3.54 ERA.

Diamond and Doumit worked their initial game plan well. They wanted to establish his fastball on each corner of the plate, and Diamond was able to do so.

Diamond threw fastballs on 14 of 17 pitches in the first inning and 10 of 12 in the second inning. He threw Cowgill four fastballs in the first inning, but two of the four pitches he threw to Cowgill in the third inning were changeups. At that point, Mets hitters began to see more changeups and curveballs from Diamond.

The approach got Diamond into the fourth inning with a shutout on two hits.

“The way the first four innings went I was pretty pumped up,” Diamond said. “That was a big step.”

The fifth inning didn’t start so well. Diamond wanted to throw a 2-0 cutter on the outside corner to Marlon Byrd but it came back over the plate. Byrd stepped into it and blasted a solo home run to left for the first run of the game.

A 3-2 fastball to Ike Davis was hit for a single to left, with Davis thrown out trying to stretch for a double. Jacob Turner hit the first pitch he saw for a single. Ruben Tejada hit a 2-2 curveball for a double. Cowgill got ahead 3-1 and hits an RBI single. Diamond got ahead of Daniel Murphy 0-2 with two curveballs, but he threw a third curveball that Murphy hit to center for an RBI single that ended Diamond’s outing.

Looking back on the inning, Diamond knew they wanted to mix in other pitches the second time through the order but he thinks he might have adjusted more than he needed to. Lesson learned, he said.

“The inning kind of sped up one me,” Diamond said. “I’ve got to do a better job of executing and do a better job of getting out of it so I can go a little deeper.”

It’s not what the Twins needed on a day in which Harvey took a no-hitter into the seventh inning, but it’s something Diamond can take off from.

“Diamond was all right for his first time back,” Twins manager Ron Gardenhire said. “Got some pitches up there in the fifth inning, but a nice performance. He was kind of cruising right along there.

“We’ll take that for his first performance of the year with us.”