NEW BRITAIN, Conn. — Brian Johnson has been a different pitcher since July 7, when he was tagged for seven runs in 21/3 innings at Binghamton.

Johnson allowed one infield single in seven innings Friday night – and Manager Billy McMillon thought it should have been scored an error – as the Portland Sea Dogs shut out the New Britain Rock Cats 1-0 before 5,451 at New Britain Stadium.

In his last three outings, Johnson has surrendered one earned run over 20 innings, going 2-0 with an ERA of 0.45.

On Friday, he walked three and struck out a season-high 12. The hit he gave up came in the third inning.

“It’s one outing,” Johnson said of his start against Binghamton. “I think I got ahead of myself and I fell behind in the court. (On Friday), I had fastball command and that’s what usually leads to my success.”

The Sea Dogs scored in the top of the third against Adrian Salcedo, who was making a spot start for the Rock Cats after Jason Wheeler was promoted to Triple-A Rochester earlier in the day.

Shannon Wilkerson led off with a single, raced to third on Blake Swihart’s single to right and scored on Sean Coyle’s sacrifice.

New Britain was awarded its first hit when third baseman Michael Almanzar fielded Kyle Knudson’s grounder behind the bag, then threw low to first on a long throw. The play was changed to an error after the game. Stephen Wickens then reached when shortstop Ryan Dent couldn’t field his grounder up the middle.

“I think we threw a no-hitter,” McMillon said. “I think both of those hits are errors. I can’t understand how the scorer gave both of those hits.”

Portland snapped a two-game skid and evened the four-game set against the Rock Cats at a win apiece.

In his previous outing, Johnson didn’t receive a decision despite yielding one unearned run over six innings Sunday in a 3-2 loss at New Hampshire.

Johnson walked two in the seventh but struck out Brad Boyer to preserve the lead.

“I was rushing my delivery a little bit and I was pulling off,” Johnson said. “(Pitching coach Bob) Kipper came out to the mound and we talked about it.”

“Brian did a really good job,” McMillon said. “He got ahead, he was able to mix in some quality off-speed (pitches). He worked quick. He threw a lot of strikes.”

Noe Ramirez recorded the final six outs for his 11th save in as many chances.

Swihart continued to tear apart New Britain pitching with three hits to raise his batting average against the Rock Cats to .400 (20 for 50) this season.

Otherwise the Sea Dogs have gone into a batting slump, managing just four runs in their last three games. They suffered a 7-1 loss to New Britain on Thursday.

The Sea Dogs did have their chances Friday, getting at least one runner on in each of the first eight innings, and stranded eight.

Normally a reliever, Salcedo was pulled after just three innings, allowing three hits.

While Portland, which leads the division by 41/2 games as Binghamton also won, has lost two 1-0 games this season, this was its first win of the season by that score.