The Red Sox will start left-hander Drew Pomeranz (1-5, 6.56 ERA) against Blue Jays right-hander Marcus Stroman (4-8, 5.63) in the opener.
The Red Sox (79-34) are coming off the high of a four-game sweep of their longtime rivals, the New York Yankees, that included a game-tying, three-run ninth inning Sunday night at Fenway Park and a 5-4, 10-inning win.
Boston is 7-0-2 in its past nine series.
"I'm proud of them," Red Sox manager Alex Cora said. "They're playing well. They don't get caught up in the whole thing. They show up every day. They digest the information. They go out there and play and they win games. They win a lot of games."
The Blue Jays (51-60), meanwhile, failed to compete their own four-game sweep of the Seattle Mariners on Sunday afternoon when they lost 6-3 at Safeco Field, completing a 5-5 road trip. As usual in Seattle, there was a huge attendance of Blue Jays fans, most of them from western Canada, where baseball fans have made Toronto's series in Seattle each season an annual trek.
"It's unique here. You're not going to find this anywhere else," Blue Jays manager John Gibbons said. "Wins have been few and far between this year and they got to see three of them."
Wins may have been scarce for the Blue Jays this season, but the Red Sox can hardly do anything but win during what has been a magical season.
The Red Sox's winning percentage of .699 matches the fourth-best record through 113 games since divisions were introduced in 1969. Those other teams -- the 1998 Yankees, the 2001 Mariners, 2017 Los Angeles Dodgers and 1969 Baltimore Orioles -- averaged 111 regular-season victories with only the 1998 Yankees going on to win the World Series.
The Red Sox need only to go 21-27 for the rest of the season to post their first 100-win season since 1946.
By going 27-21, they would surpass the 1912 Red Sox, who had a franchise-record 105 wins.
"It's fun," Red Sox outfielder J.D. Martinez said. "This is a fun team. It's a very humble team, I feel like. We don't have any of those egos on this team. It seems like a close group of guys, guys who like to have fun."
Martinez was a key free-agent acquisition for the Red Sox this past offseason. He is batting .324/.392/.641 with 33 homers and 93 RBIs.
The Blue Jays will be facing an old teammate in outfielder/infielder Steve Pearce, who was traded to Boston at the end of June and has batted .333/.431/.667 with five homers and 14 RBIs for Boston in 20 games. He had three homers in the opener of the four-game sweep of the Yankees and another in the second game.
There have been some bright spots lately for the Blue Jays, despite unloading pitchers J.A. Happ, Roberto Osuna, Seunghwan Oh and John Axford in trades before the July 31 deadline for deals without waivers. There could be other trades during August.
Blue Jays shortstop Aledmys Diaz had five home runs during the past trip, including a two-run shot that temporarily tied the score on Sunday. He batted .357 (10-for-28) with seven RBIs on the trip.
"Playing every day gives you a little more confidence and I've been swinging at good pitches," Diaz said. "I've been a little more patient and putting good wood on good pitches."
Blue Jays first baseman Justin Smoak is on a season-best 10-game hit streak, batting .302 (13-for-43).
Pomeranz will be making his third start since a spell on the disabled list June 2-July 23 with biceps tendinitis. He allowed two runs in five innings to the Philadelphia Phillies on July 31 and four runs in 4 1/3 innings on July 24 against the Baltimore Orioles.
In nine career games against Toronto (seven starts), Pomeranz is 3-2 with a 4.32 ERA. He is 2-1 with a 3.74 ERA at the Rogers Centre.
Stroman had won his two previous starts before he lost to the Oakland Athletics on Aug. 1, allowing 11 hits and seven runs in five innings. He is 0-1 with a 5.40 ERA in one start against the Red Sox this season and is 4-3 with 4.28 against them in 11 career starts.