"I wasn't tired. I don't know. I can't explain what happened," said Doubront. "I was feeling really good during the first two innings and the whole day, and in my bullpen and the start of the game. I started doing too much. I think that's what happened. I was trying to do too much and overthrow."
Down big early, the Red Sox never recovered as a tough first homestand continued.
Boston is 1-4 at Fenway, and 3-5 on the season, thus far unable to find a steady rhythm on either side of the ball.
"I don't think we're scuffling," said left fielder Jonny Gomes. "I just don't think we've started. It's too early in the season, offensively, defensively, pitching, to say we're scuffling. The starters are barely cracking 40 at-bats right now. We just have to put a positive nine together and then we'll roll."
Doubront's pitching line (2 2/3 innings, 6 hits, 5 runs, 3 walks) was one he'd like to forget.
Instead of keeping his team within striking range, reliever Burke Badenhop allowed the Rangers to stretch the lead further when he gave up five hits and four runs over 2 1/3 innings.
The Red Sox led off the first seven innings by reaching base, only to ground into five double plays over that span.
"That's a pitcher's best friend," said Gomes. "It's early in the season. You want to look at the positive side of things, and five double plays when we scored seven runs, I'm sure that's pretty rare too. I like where we're at. If we can score seven runs with five double plays, I think we're scratching the surface of some things on the positive side."
There was a brief glimmer of hope in the bottom of the seventh, when an RBI single by A.J. Pierzynski and a two-run double by Jackie Bradley Jr. cut the deficit to 9-4.
At that point, the Fenway crowd was on its feet, hoping for a full-fledged comeback that never happened.
"It was a sense that a rally was starting to happen. The crowd was getting behind the team," said Bradley, who had his second straight multi-hit game. "It's great when fans are like that and support you through the tough times."
But Gomes struck out and Dustin Pedroia tapped out to the mound, ending that threat.
"In this ballpark, late in games, those guys have taken away a lot of ballgames," Rangers manager Ron Washington said. "We needed every run tonight."
There were no signs of the type of meltdown that was in store for Doubront when he cruised through the first two innings, facing just seven batters.
But in the third, it all fell apart. Robinson Chrinos opened with a solo homer to left. Prince Fielder hammered a one-out, RBI double to right. Adrian Beltre followed with an RBI single to left that brought home Fielder. Donnie Murphy hit a liner to center that seemed to freeze Grady Sizemore, and it deflected off his glove for an RBI double to make it 5-0.
Doubront, taxed from what would turn into a 38-pitch inning, walked the next two batters and was removed from the game.
With the Red Sox already down 8-0, Mike Napoli put his team on the board in the fourth with an RBI single.
"Playing catchup is tough, especially at this level," said Gomes.
There were some bright spots for Boston in defeat.
Brandon Workman fired four solid innings, giving up two hits and a run. He was optioned to Triple-A Pawtucket following the game because the Red Sox needed a roster spot to activate Craig Breslow for Wednesday's game.
"Breslow obviously deserves a spot here. That's the way it goes," Workman said.
And Pierzynski, who had a tough first week, responded with his second consecutive three-hit game.
"It's amazing when you get hits how much better people think you are," said Pierzynski. "I mean, obviously you want to get hits and want to win games. You want to help contribute to winning games. You get hits, but when you lose it doesn't really make a difference. We got a bunch of hits tonight, we scored seven runs, but when you give up 10 it's tough."