BOSTON — The best record in the majors, another strong performance by John Lackey, an excellent chance to take the lead in the ninth inning — all just wasted by the Los Angeles Angels.

One night after snapping an 11-game postseason losing streak against the defending World Series champions, Los Angeles lost 3-2 Monday night as Boston advanced to the AL Championship Series starting Friday night at Tampa Bay.

The Angels: winners of the AL West by 21 games, eliminated in just four.

"It's naturally disappointing," manager Mike Scioscia said. "But we're going to have to keep trying to get better. That's all we can do."

The Angels lost to the Red Sox in the first round of the postseason for the second straight year — and for third time in five years — after dominating their division all season.

"Those guys have certainly, in the last three series that we've been involved with them, they've beaten us," Scioscia said of the Red Sox.

"I thought we played much better this series than going back to '04 or '07 against them. It's naturally disappointing. But we're going to have to keep trying to get better. That's all we can do."

The Angels won eight of nine regular-season games against the Red Sox but lost the best-of-five series when rookie Jed Lowrie's two-out single off Scot Shields drove in Jason Bay with the winning run in the ninth. Bay slid in ahead of right fielder Reggie Willits' throw.

"Once I turned around, I knew it was going to fall in," Shields said. "I said, All right, ballgame.' But Reggie did a heck of a job to make that close."

In a series filled with missed opportunities for the Angels, the final — and perhaps the costliest — one occurred in the final inning.

Pinch hitter Kendry Morales hit a leadoff double, and Willits, running for Morales, advanced on Howie Kendrick's sacrifice.

Erick Aybar took the first two pitches from Manny Delcarmen for balls. Then came the play Scioscia may be thinking about long into the offseason, even though Delcarmen was expected to throw the ball over the plate.

Aybar, who drove in the go-ahead run in Sunday night's win, squared around to bunt and missed as Willits started for home. Catcher Jason Varitek chased him back toward third and tagged him about a step from the base. Varitek tumbled and the ball fell out of his glove as he hit the ground. Scioscia argued, but umpire Tim Welke stuck to his out call.

"I feel he had to have control of the ball," Scioscia said. "Tim Welke felt that the tag was made and the out was recorded before he lost the ball."

Willits had confidence in Aybar.

"He's unbelievable at the plate, whether he's bunting or whether he's hitting," Willits said. "Everybody in the world can second-guess it, but if it worked, people would have said it's the greatest play in the world."

Torii Hunter hit a tying two-run single for the Angels in the eighth and was 5 for 11 with runners in scoring position in the series. The rest of the team had three hits in those situations.

Lackey had little support — again.

He was outdueled by Jon Lester in the series opener, a 4-1 Red Sox win in which the Angels were 1 for7 with runners in scoring position. They led 1-0 through five innings before Lackey gave up Bay's two-run homer in the sixth. The right-hander allowed just those two runs in 623 innings. Lester gave up one in seven.

Game 4 Monday night: same matchup, same result.

"Lackey is a bulldog, man," Hunter said. "I love Lackey when he's on the mound. He deserves a lot more run support, especially in the playoffs."

Lackey is 0-3 in six postseason starts since winning Game 7 of the World Series against the San Francisco Giants in 2002. On Monday night, he allowed two runs in seven innings but left trailing 2-0.

Los Angeles could lose two of its best players before next season. First baseman Mark Teixeira, acquired from Atlanta in July, and Francisco Rodriguez, who set a major league record with 62 saves this year, both can become free agents.

"This is the most talented team I've been around," Shields said.

With a mixture of sadness at being eliminated and uncertainty about the future, Rodriguez talked quietly as he dressed at his locker for the flight home.

"You pinch me right now, I'm about to cry. I don't know what to think," Rodriguez said. "I don't even know what's going to happen to me. I don't know what to say, what to think, what to do."

Note: Third baseman Mike Lowell was removed from Boston's roster before the game because of a right hip strain. Last year's World Series MVP is ineligible to play in the ALCS. Lowell also has a torn labrum in his right hip.