BOSTON — Clay Buchholz gave Boston’s struggling big-name rotation a lift with his best performance of the season.

Buchholz, a right-hander who began the year with 12 career wins, allowed two runs on five hits in eight-plus innings, David Ortiz hit a two-run homer and the Red Sox beat the Minnesota Twins 3-2 on a rainy Wednesday night.

Buchholz began spring training competing with Tim Wakefield for a spot in the rotation behind Josh Beckett, Jon Lester, John Lackey and Daisuke Matsuzaka. Now his ERA of 3.26 is better than all of theirs.

“I think anybody on the staff can take the responsibility to” pick up the rotation, the 25-year-old Buchholz said. “I definitely wanted to go out and get deep into the game.”

Buchholz (5-3) left after allowing a leadoff single to Denard Span in the ninth. Daniel Bard gave up a run on Joe Mauer’s groundout, then worked out of a first-and-second jam and picked up his first save of the year and second of his career by retiring Jim Thome on a groundout.

In six of his eight starts this year, Buchholz allowed three or fewer earned runs. And dating back to last Aug. 19, his 11 wins are the most by any American League pitcher. Andy Pettitte, David Price and Justin Verlander have 10 each.

“I felt like I picked up where I left off last year” when he won six of his last seven decisions, Buchholz said. “You gain confidence from doing well.”

He’s become a solid part of the rotation after spending the last three seasons in and out of it.

In his previous start, Buchholz gave up one run on three hits and five walks in 61/3 innings in a 7-2 win at Detroit. In between, four other starters allowed at least four runs in their outings. And now Beckett is on the 15-day disabled list with a lower-back strain and Matsuzaka is coming off a horrible start after which he criticized Victor Martinez’s pitch calling.

Martinez had no such problems with Buchholz, who was sharp with his fastball, slider, curve and change-up.

“It’s pretty tough to face a pitcher when he’s got all his pitches working,” the catcher said. “You don’t even know what to look for.”

Buchholz struck out seven, walked one and faced only four batters over the minimum. But the Twins took a 1-0 lead in the fourth on doubles by Span and Mauer. Then Buchholz retired Justin Morneau on a called third strike and got Michael Cuddyer on a groundout on the wet infield.

“I’ve played in worse (conditions),” Morneau said. “Buchholz hit his spots. He had the fastball getting up around 94, 95 (mph) and was throwing that slider on the outer part, (but) you always have the curveball in the back of your mind.”

After Mauer’s double, Buchholz retired the next nine batters before allowing a single to Morneau in the seventh. Cuddyer ended the inning by grounding into a double play.

The Red Sox went ahead in the fourth on Ortiz’s two-run homer off Scott Baker (4-4) after a single by Martinez. The umpires first ruled the high drive to left center didn’t clear the red home-run line. But they reviewed it and awarded a homer to Ortiz, his eighth of the year and fourth in six games.

Boston made it 3-1 in the sixth after Baker retired the first two batters. Adrian Beltre and Jeremy Hermida singled, and Bill Hall singled in Beltre.

The victory improved Boston’s record to 5-11 against Tampa Bay, New York and Minnesota, the top three teams in the American League.