DETROIT (AP) — Allen Webster let a two-run lead slip away in a matter of minutes.
Boston couldn't afford that against Max Scherzer and the Tigers.
Scherzer won his 11th straight decision to start the season and Victor Martinez hit a first-inning grand slam to lead Detroit to a 10-3 victory over the Red Sox on Saturday night.
Boston scored twice off Scherzer in the first, but after Martinez put the Tigers ahead, the Red Sox couldn't muster much offense against the Detroit right-hander.
Webster (0-2) gave up five runs and eight hits in 4 1-3 innings. He struck out five and walked two.
"The four runs given back in the first set the tone for the entire evening," Boston manager John Farrell said. "I think he settled down after the first inning and pitched OK."
Scherzer (11-0) allowed a couple of runs in the first, including a towering solo homer by David Ortiz, but Martinez's drive put the Tigers ahead to stay.
Martinez also hit an RBI double in the fifth, and Scherzer shut down Boston after the first. He allowed two runs and six hits in seven innings.
Red Sox reliever Franklin Morales yielded four runs, including a two-run homer by Omar Infante. Farrell said Morales could go on the disabled list because of left shoulder discomfort.
Scherzer became the first pitcher to start 11-0 since Roger Clemens in 1997, according to STATS. The last to start 12-0 also was Clemens, during a 14-0 stretch to begin his AL MVP season for the Red Sox in 1986.
"I realize that it takes so many other teammates to put me in that position," Scherzer said. "This is a credit to the Detroit Tigers, for me being in this position. I know I've pitched well, and I know I've given my team a chance to win, but it doesn't always go that way."
The first two hitters singled off Scherzer, and Dustin Pedroia's double-play grounder gave Boston a 1-0 lead. Ortiz's 16th homer put the Red Sox up by two.
Detroit erased that deficit in a hurry. After singles by Austin Jackson and Torii Hunter, Miguel Cabrera drew a walk. Prince Fielder struck out, but Martinez's line drive cleared the wall in right for his third career slam.
"The team gives me a lead and they hit two groundballs and a walk," Webster said. "Left one over the middle and (Martinez) hit it hard."
Webster was called up from the minors before the game to make this start. Boston is without its own unbeaten starter: Clay Buchholz (9-0) is recovering from a strained neck.
Jose Iglesias appeared to have a double off Scherzer in the fifth, but he stumbled past second base while beating Hunter's throw from right field and was tagged out.
Ortiz hit a drive in the sixth that Jackson ran down in deep left-center. Scherzer struck out his final batter in the seventh — Jarrod Saltalamacchia — for his sixth strikeout. He's reached that mark in all 15 starts this year.
The Tigers, meanwhile, kept adding runs. Andy Dirks singled, stole second and scored on Jackson's single in the fourth. Webster was lifted with nobody on in the fifth, and Morales allowed a walk to Fielder, a run-scoring double by Martinez and an RBI single by Jhonny Peralta.
Infante's homer in the seventh made it 9-2. Fielder hit into a bases-loaded double play in the eighth, bringing another run home.
Saltalamacchia hit an RBI single in the ninth.
NOTES: Jackson, Hunter and Dirks all had three hits. ... Ortiz's 18 homers at Comerica Park are the most there by a visiting player, according to STATS. ... For a second straight night, Shane Victorino tried to throw out Cabrera at first base from right field on what looked like a clean single. Cabrera has beaten the throw both times. Victorino also tried it on a hard single by Hunter and nearly got him. In the ninth, Hunter charged Ortiz's single as if he wanted to try to throw to first, but Fielder wasn't covering the bag. ... Detroit C Alex Avila (bruised left forearm) is expected to be with Triple-A Toledo on Sunday for a rehab assignment. He has been on the DL since June 17 and expects to be ready when he's eligible to come off. ... Boston LHP Felix Doubront (4-3) faces Detroit ace Justin Verlander (8-5) on Sunday.