BALTIMORE – Jon Lester remains at a loss when asked to explain all his wins over the Baltimore Orioles.

The left-hander is just happy he could end a two-game Boston slide, help the Red Sox finish a road swing on an upbeat note and get his team out of last place in the American League East.

Lester improved to 14-0 all-time against Baltimore with eight dominating innings, Dustin Pedroia hit a tie-breaking infield single and the Red Sox averted a sweep with a 6-2 victory over the Orioles on Thursday night.

“If I knew the answer to that, I’d do well against everybody,” Lester said, shaking his head. “I just pitch well against this team. … I just really don’t know.

“I’m aware of the track record I have against them, but I don’t know how to explain it. I feel comfortable against them. I really like pitching here at this park, I’ve always felt good here.”

Lester (3-1) is unbeaten in 17 career starts versus the Orioles and boasts the longest active winning streak by any pitcher against one team. He yielded two runs on four hits, walked three and struck out five.

“He threw his change-up about as good as he’s ever thrown,” Red Sox Manager Terry Francona said. “Some of those hitters, he really slowed them down. He was really good and he needed to be to give us enough time. He gave us a chance.”

After Derrek Lee’s RBI single in the first, Lester didn’t allow another hit until Vladimir Guerrero’s solo homer with two outs in the sixth.

It was 2-all when Carl Crawford doubled off Jim Johnson (1-1) to the start the seventh. Crawford held second when Marco Scutaro couldn’t execute a sacrifice bunt, took third on Jacoby Ellsbury’s grounder and scored when third baseman Mark Reynolds bobbled Pedroia’s slow roller.

Baltimore fell into last place in the AL East, a half-game behind the Red Sox, who finished 6-3 on a nine-game road trip.

“It’s great to finish up this road trip the way we did,” Lester said. “The guys are starting to feel a little bit better about themselves now, and hopefully we can go home and really start playing well.

“To go 6-3 on this road trip, we’ll take it, the way we started off the season.”

Boston’s Adrian Gonzalez had three hits and two RBI.

Ellsbury led off the game with a double and scored on Gonzalez’s one-out double for a 1-0 lead.

The Orioles tied it in the bottom half when Brian Roberts drew a leadoff walk, moved to second on Nick Markakis’ single, stole third and scored on Lee’s single, which ended an 0-for-14 slump with runners in scoring position.

Ellsbury and Gonzalez teamed again to put the Red Sox up 2-1 in the third. Ellsbury singled with one down, moved to second on a groundout and came home on Gonzalez’s single.

Guerrero tied it in the sixth with a shot to left off a full-count fastball from Lester, who surrendered a home run for the first time in five starts. It was Guerrero’s fourth homer of the season.

Baltimore starter Brad Bergesen went six innings, allowing two runs on six hits. He walked two and struck out five.

“The body of work was pretty good. I thought (Bergesen) gave us a good chance to win against a good-hitting club, and I was proud of him,” Orioles Manager Buck Showalter said.