BOSTON -- Chris Tillman did what aces are supposed to do.
With his team in danger of being swept in an important three-game series against the first-place Boston Red Sox, the tall right-hander pitched seven strong innings Thursday, leading the Baltimore Orioles to a 3-2 victory at Fenway Park.
Thanks largely to the efforts of Tillman (15-4), the Orioles head to New York for a weekend series against the Yankees 6 1/2 games behind the Red Sox in the American League East and 3 1/2 games out in the AL wild-card chase.
"That's the starting pitcher's goal, for these guys to trust you every time you go out there," Tillman said after and becoming the fourth 15-game winner in the major leagues. He earned his first win in five starts since Aug. 2.
Asked what the 15th win meant to him, he said, "Big. I think more importantly for the team. The (other) stuff is kind of eyewash to me. It was big to get that win tonight."
Tillman, continuing his mastery of Boston, allowed six hits and didn't walk anyone while striking out eight. Three relievers finished up. Brian Matusz struck out David Ortiz with the tying run on third and two outs to end the eighth, and Jim Johnson pitched the ninth for his 41st save in 50 chances.
Manny Machado stroked a two-run double in the third inning to lead the Baltimore offense, which hit just enough for Tillman, Baltimore's first 15-game winner since Erik Bedard in 2006, to outpitch Jon Lester.
The win also snapped an eight-game losing streak in one-run games for Baltimore. The Orioles went 29-9 in such decisions in making the playoffs last year but are just 15-24 in the tightest games this year.
"We've got 30 games left, and September is an eternity," Baltimore manager Buck Showalter said. "It's a long season. It starts here shortly and it'll edge by, and that that'll be good for us if we're trying to catch up."
Tillman, 8-1 on the road this season, improved to 4-1 with a 2.15 ERA in nine lifetime starts against the Red Sox. He is the first pitcher with three wins over Boston this season, and he has a 1.93 ERA in four career starts at Fenway Park.
Boston had its four-game winning streak snapped, and it remained 2 1/2 games ahead of the losing Tampa Bay Rays atop the AL East.
Red Sox right fielder Shane Victorino, a switch hitter batting right-handed against righties because of his hamstring problem, hit a solo homer in the sixth inning to cut Baltimore's lead to 3-2. It was his 12th homer of the season and team-high seventh this month. It was also the first homer any member of the current Boston roster has hit off Tillman, with the current Red Sox batting a combined .190 against him.
Lester, 14-1 against the Orioles coming into this season, fell to 1-2 on the year against the Orioles.
"I thought he had good stuff once again," Boston manager John Farrell said of Lester, who had a two-start winning streak snapped. "A couple of pitches found the middle of the plate. He was strong and kind of grinding through some things tonight to give us six strong innings with three runs allowed."
Ortiz went 0-for-4, leaving him in an 0-for-22 spin. His longest hitless streak with the Red Sox is 23 at-bats, in 2011. He is also 1-for-19 with 11 strikeouts lifetime against Matusz.
"(Stuff) happens. It's not the end of the world," Ortiz said. "Even Papi struggles. I'll be back."
Daniel Nava had three hits, and Jacoby Ellsbury stole his 50th base of the season for the Red Sox -- Ellsbury's third 50-steal season, his first since 2009.
NOTES: Orioles CF Adam Jones snapped his bat and an 0-for-11 skid with an infield hit in the third inning. He added another infield hit later. ... The Orioles reportedly put in waiver claims on Minnesota OF Josh Willingham and Seattle OF Michael Morse and could be working out a deal for one, not likely both. ... Boston RHP Ryan Dempster, pitching for the first time since being suspended for five games after hitting Yankees 3B Alex Rodriguez, returns Friday to face the Chicago White Sox in the opener of a three-game weekend series. RHP Miguel Gonzalez pitches for the Orioles in their opener in New York. ... Red Sox 1B Mike Carp was a late scratch with left shoulder soreness. ... Boston RHP Clay Buchholz will make two more rehab starts, both likely with Triple-A Pawtucket, and appears on target to pitch for Boston at Tampa Bay on Sept. 10. ... RHP Jason Hammel, out with a right forearm strain, pitched 3 2/3 shutout innings for Baltimore's Double-A Bowie team in his first rehab start Thursday night. He's expected to pitch in the minors once more before rejoining the Orioles. ... NESN, which televises Red Sox games, announced broadcaster Jerry Remy will not return this season and hopes to return in 2014. His son, Jared, has been charged in the stabbing death of his girlfriend.