BOSTON – John Lackey certainly looks and sounds fully recovered from elbow-ligament replacement surgery. It shows both on and off the mound.

Lackey struck out a season-high 12 over seven strong innings and Daniel Nava drove in two runs, leading the Boston Red Sox to a 5-3 victory Wednesday and a sweep of the two-game series against the Colorado Rockies.

“Probably the strongest he’s been all year,” Boston Manager John Farrell said. “Outstanding fastball command, good power to it and a lot of strikes.”

The 34-year old right-hander gave up two runs and eight hits without walking a batter. Mixing a fastball and slider most of the time, he threw 73 of 98 pitches for strikes.

Lackey (5-5), who missed all of last season rehabbing from the Tommy John surgery, struck out nine over the first four innings while allowing Wilin Rosario’s first-inning RBI single.

“I’ve been feeling pretty good,” Lackey said, often breaking into smiles and joking, a big change from his demeanor in his early days in Boston. “I still feel like I’m getting stronger. It was a process, a lot of work, I’m still building.”

With the top two starters in the rotation — Jon Lester and Clay Buchholz — both going through tough stretches, Lackey knows he’s been one to pitch in big games.

“Jon will be fine. Clay has done great. I’m not worried about those guys,” he said. “I’ve been the guy that has gone first in playoff games.”

Lester has struggled after a strong start, losing three of his last four decisions. Buchholz is on the 15-day disabled with a neck strain.

Lackey had his 14th career double-digit strikeout game, first since Oct. 3, 2010.

“It speaks to where my stuff’s at right now,” he said of the strikeouts.

Shane Victorino had three hits and Dustin Pedroia added two for the Red Sox.

Roy Oswalt (0-2) allowed five runs and nine hits in six innings, striking out five and walking one.

Colorado’s Michael Cuddyer extended his hitting streak to 23 games with two solo homers, matching Dante Bichette’s club-record set in 1995.

“The Red Sox are good at putting the ball in play and creating some things. It was a lot of contact, a lot of action, and I just think they found some holes early,” Rockies Manager Walt Weiss said.

The Rockies finished a trip in which they lost 7 of 9.

New Boston closer Koji Uehara worked a perfect ninth for his second save.

The Red Sox wasted little time jumping to a 3-1 lead against Oswalt in the first. Jacoby Ellsbury had a leadoff double and scored on Victorino’s single to right. David Ortiz followed with his 499th career double. Nava then had an RBI single.

Oswalt, 3-2 with a 2.16 ERA at Double-A Tulsa, struck out 11 without allowing a walk in his first start against Washington last Thursday.

“I felt like both starts actually were better than what they turned out to be,” he said. “That’s baseball, you know? Maybe the next two starts I get some lucky breaks.”

Boston increased it to 5-1 in the third on Mike Napoli’s bases-loaded RBI single. In the sixth, the Rockies cut it to 5-2 on Cuddyer’s leadoff homer .

They had runners on first and third with one out before Lackey struck out Tyler Colvin and got Yorvit Torrealba on a liner to center.

In the eighth, Cuddyer homered against Junichi Tazawa.

Colorado had grabbed a 1-0 lead when Rosario singled in Carlos Gonzalez.