TORONTO — The conditions weren’t favorable to begin with for the Red Sox. Then, Dustin McGowan and Frank Thomas made them worse.

Short on both sleep and manpower, the Red Sox were no match for the Toronto Blue Jays starting pitcher and designated hitter. McGowan subdued a lineup without Manny Ramirez and Kevin Youkilis, checking the Sox on a complete-game five-hitter while Thomas enjoyed the second three-homer game of his career as the Jays bounced the Sox, 6-1.

The loss was Boston’s third in the last four games and enabled the New York Yankees to move within 3½ games of their lead in the American League East. The Sox’ lead hasn’t been this small since May 1.

Tim Wakefield (six innings, four runs) pitched better than he had in weeks, but was victimized by Thomas, who moved into a three-way tie for 18th place on the all-time home run list. Thomas now has 512 homers, pulling him even with Ernie Banks and Eddie Matthews.

Thomas hit his third homer of the night off Kyle Snyder in the eighth. He produced five of the Jays’ six runs.

The only other Toronto run came in the fifth when the Jays used a walk, an infield single and a fielder’s choice to go up 3-1.

“I felt like I had good stuff,” said Wakefield, 16-11. “I’d like to have just two pitches back — both to Frank.”

Only once before last night did Thomas have a three-homer game — Sept. 15, 1996. That, too, came in a game in which Wakefield started.

“I remember it like it was yesterday,” said a rueful Wakefield. “There’s a reason he’s got (512) homers — if you make a mistake to him, it’s going to leave the yard pretty quickly.”

The loss extended Wakefield’s winless streak to three games, but his effort was far better than his last two outings. In those starts, which came after he was sidelined by back spasms, he failed to get through the fourth inning.

“Physically, I felt great,” said Wakefield. “I thought I had great movement. I’m not happy with the (pitching) line, but I’m happy with how I felt.”

Once more, Wakefield was the victim of poor support from his teammates. In his last 14 losses, dating back to June 15, 2006, the Sox have scored a grand total of 16 runs. Last night was no different as the Sox accomplished little against McGowan, who retired the first 12 hitters he faced.

A leadoff single by Jacoby Ellsbury in the fifth, followed by a groundout and a two-out double to left from Mike Lowell put the Sox on the scoreboard, but McGowan retired the next 12 hitters he faced before a two-out double by Alex Cora in the eighth.

“(McGowan) had has his A-plus game tonight,” said Wakefield in admiration.

“He had a fastball in the upper 90s,” said manager Terry Francona, “but it was his slider that made it difficult. He’s got a power slider and we had a lot of trouble with it.”

It was McGowan’s second complete game of the season — he has a one-hitter against Colorado in June — and marked the third time in his last four starts that he’s gone at least eight innings. Seventeen of his last 22 outings have resulted in quality starts.

It helped McGowan that the Sox were operating without much rest — they arrived at their Toronto hotel shortly before 4 a.m. yesterday — and were missing Ramirez (oblique strain) and Youkilis (wrist). David Ortiz has experienced soreness in his knee the last few days and was operating at less than full strength.

Through seven innings, McGowan, who didn’t walk a batter all night, had allowed just two baserunners.

“We’re going to have to fight through (an undermanned lineup) the next couple of days,” acknowledged Francona. “That’s OK. That’s what good teams do.”

“You don’t want to make excuses,” said Wakefield, “but it’s tough to play (at less than full strength).”

smcadam@projo.com