The knuckleballer helped Boston pull into a tie for the AL East lead on Tuesday with a 3-1 victory over the Toronto Blue Jays in the opening game of a day-night doubleheader.
Then he left, still strong after seven innings, so he would be fresh for a crucial start on three days' rest against the New York Yankees.
"I probably could have finished the game, but I don't think that's a smart move," he said after holding the Blue Jays to one unearned run on three hits. "It's a pennant race. Every game is pretty much a must-win."
The Red Sox were tied with the Yankees heading into the nightcap of the split-admission doubleheader, a result of Monday's rainout. The Yankees were scheduled to play the plummeting Orioles, losers of nine straight, in Baltimore.
David Ortiz drove in two runs to give him a major league-leading 142 RBI and help the defending World Series champions win for the fourth time in a row and their fifth in six tries.
The victory guaranteed that the AL East title will be up for grabs when New York comes to Fenway Park for a three-game, season-ending series this weekend.
Wakefield (16-11) was scheduled to pitch the regular-season finale on Sunday, but Monday's rainout pushed Curt Schilling back until Tuesday's nightcap, when he was to face Gustavo Chacin. The Red Sox decided that the knuckleballer was better equipped to come back on short rest than Schilling, who has struggled all season as he recovers from ankle surgery.
So out came Wakefield.
"You never want to look past anything," Boston manager Terry Francona said. "But it's a little bit of an extraordinary circumstance."
Boston, the Yankees and Cleveland were knotted up in the AL wild-card race with 92-64 records.
Wakefield allowed walked one and hit a batter while striking out six to win for the eighth time in 10 decisions. Jonathan Papelbon followed him in the eighth, using a mid-90s fastball and the late afternoon shadows to escape a first-and-third, one-out jam.
First baseman John Olerud raced into the Fenway shadows to run down Vernon Wells' popup, then Papelbon blew a fastball past former Red Sox infielder Shea Hillenbrand for strike three to end the inning.
"That's tough," designated hitter Frank Catalanotto said. "The toughest part was the shadows. We all came back saying we couldn't see the ball. It was tough picking it up. When you go from a slow knuckleball to a guy throwing 95 and you add in the shadow, it's tough."
Mike Timlin pitched the ninth for his 12th save in 19 chances and his 79th appearance of the season -- one short of the franchise record.
Dave Bush (5-11) allowed three runs on six hits in six innings, striking out five and walking two. He ran into trouble in the first when Johnny Damon led off with a single and Edgar Renteria doubled him to third.
Ortiz grounded out to second to make it 1-0, then Manny Ramirez singled to score Renteria.
Ortiz doubled to score Renteria in the fifth and make it 3-1.
- The Red Sox face three consecutive left-handed starters, starting with Chacin. Lefty starters are 5-10 with a 6.59 ERA at Fenway this year.
- Because of Monday's rainout, Schilling will start the regular-season finale against Mike Mussina instead of Saturday's game against the Yankees. Wakefield will start on three days' rest on Saturday and face Randy Johnson. David Wells and Chien-Ming Wang will pitch Friday's series opener.
- Wakefield's previous two starts were no-decisions, including a nine-inning stint that Boston won on a walkoff hit-by-pitch in the 10th.