Lester had been 14-0 lifetime against Baltimore.
BOSTON - Jon Lester has lost to the Orioles, and the Red Sox world we have known has officially ceased to exist.
In good times and bad, the Boston left-hander has had the O's number. That number was up Friday night, when Baltimore won 4-2 at Fenway Park.
"It was bound to happen. They've always had a good offense, but they're putting it all together this year,'' said Lester, who had been 14-0 in 20 previous career starts against the O's.
Just as the outcome ended Lester's mastery of the Orioles, it added to the misery of a woebegone Sox season.
Boston's 17th loss in 23 games left the Red Sox 16 games under .500, matching their lowest ebb this season.
Baltimore trails New York by a game in the American League East. They stand alone in the top wild card spot.
"(Orioles manager) Buck Showalter has done a good job changing the mentality over there, and they've done a good job filling in the pieces. They're putting it all together,'' Lester said.
Lester was done in by Orioles catcher Matt Wieters, who had two hits and three RBIs.
Wieters is a .382 lifetime hitter against Lester. A single went down the line in right, and a double hugged the line in left.
""He's always done a good job getting the barrel of the bat down on me. The process was there for us, the game plan was there, but it just didn't work,'' said Lester (9-13).
Lester's 14-game winning streak was the second longest by one pitcher against one team over the last 50 years.
Only Roy Oswalt's 15-0 start against Cincinnati from 2001-05 was longer.
Red Sox manager Bobby Valentine thinks Lester's biggest problem has been non-support.
"Wieters hit a couple of balls that were barely fair. If Jon pitches like he's done the second half of the season, he's going to win a lot of games,'' Valentine said.
"We don't get the runs to give him a cushion. He always has to make crucial pitches. Sometimes it doesn't work.''
Jim Johnson's 46th save set a record for a record for a franchise that was once the St. Louis Browns.
Baltimore is 52-21 in games decided by one or two runs. In two-run games, they are 25-13.
"They know they can play the close games. The bullpen has been shut-down, and they know they can get the onr run (to win),'' Valentine said.
Dustin Pedroia's fifth-inning RBI tied the game at 2-2. With the team returning home, Valentine had offered a night off for Pedroia, whose wife just had the couple's second child.
Pedroia hates to miss games, though, and insisted on playing.
Lester has two more starts this year. He does not want to talk about next year.
"We're not fortune tellers. We don't know what they're going to do about trades or free agents,'' the pitcher said.
"All I can do it try to work on the adjustments we've made in the second half of the season and give my team a chance (in his final 2012 starts).''
The Red Sox were without Jacoby Ellsbury, whose .360 career average against the Orioles included a 38-game hitting streak that was snapped on Aug. 16.
Valentine was evasive about Ellsbury, who apparently has an injury.
"He has a little situation that we're making sure is nothing more than a little situation,'' Valentine said.
ET CETERA: Former prisoner of war Bartlett Hastings of West Springfield, 87, was honored during the game as part of National POW/MIA Recognition Day ... Daisuke Matsuzaka is expected to get one more start. It is expected to be his last with the Red Sox, ending a six-year association. Zach Stewart, who was acquired from the White Sox in the Kevin Youkilis trade, will also get a start. Stewart, pitcher Pedro Beato and third baseman Danny Valencia were called up from Pawtucket.