McCann and Young hit three-run homers during a nine-run burst in the seventh inning, and the Yankees broke loose once again, romping past the Boston Red Sox 13-3 on Tuesday night.
Down 2-1 and held to three singles going into the sixth, the Yankees suddenly struck. They wound up scoring in double figures for the fourth time in seven games -- they had gone more than a month without doing it until a 21-5 rout at Texas last week.
"Honestly, the blunt way to say it is we have a lot of really good hitters," Young said. "Everybody's a threat right now."
Mark Teixeira hit a pair of RBI singles, and McCann, Alex Rodriguez, Carlos Beltran and Chase Headley added late doubles for the Yankees, who won for the 11th time in 15 games and have a 5 1/2-game lead in the AL East.
The Yankees have totaled 90 runs in the past 10 games.
"That's just crazy," said Young, who got three hits and scored four times.
McCann tweaked his knee late in the game and shifted to play first base. Manager Joe Girardi said the team would know more about McCann's condition Wednesday.
Boston, last in the AL East, lost its eighth straight on the road.
Masahiro Tanaka (8-4) left after Pablo Sandoval's long home run leading off the seventh got the Red Sox within 4-3. Dellin Betances escaped a second-and-third jam to end the inning despite bouncing six of his eight pitches.
"I don't think anybody was expecting it," Betances said.
Bradley wound up walking and stealing second, but Betances struck out Brock Holt.
"I didn't make it look easy," Betances said.
Highly touted Henry Owens (0-1) lost in his major league debut. He had retired 12 straight batters going into the sixth but left after Young opened with a single and Rodriguez doubled to the wall.
"Once he came out of the game, they had their way with our bullpen," Boston manager John Farrell said. "Tried to find guys that at least stem the tide, shut down an out when needed, but the way they're swinging the bat, the runs that they're scoring of late, it was not a good matchup against our bullpen tonight."
The big seventh began when shortstop Xander Bogaerts bounced a throw for an error on Jacoby Ellsbury's leadoff grounder. After a walk and an RBI single by Rodriguez, the Yankees started teeing off. Ellsbury and Young each scored twice in the inning.
"It started with an extra out," Girardi said.
McCann hit his 18th homer and drove in four runs.
The Red Sox fell on Farrell's 53rd birthday and have lost 14 of 19. They began an eight-game trip with the poorest road record in the AL and matched their worst skid away from Fenway Park since dropping their final eight in the 2012 season.
Red Sox: 2B Dustin Pedroia is expected to begin baseball activities when Boston visits Detroit this weekend. He has been on the disabled list twice this season because of a shaky left hamstring. ... OF Mookie Betts (concussion) also is set to be in Detroit to continue his recovery.
Yankees: INF-OF Dustin Ackley was put on the DL because of a strain in his lower back. The move came five days after New York got him in a trade with Seattle.
Red Sox: RHP Steven Wright (4-4, 4.53 ERA) set career highs in his last start, pitching seven innings and striking out eight to beat the White Sox.
Yankees: At 21, prized prospect Luis Severino makes his big league debut when he becomes the youngest pitcher to start in the majors this season. A right-handed pitcher, he began the year in Double-A, then went 7-0 with a 1.91 ERA in Triple-A.
Comedian Tracy Morgan, born in the Bronx, drew a big cheer when he was shown on the scoreboard, and he acknowledged the ovation from his front-row seat. Morgan was critically injured in a six-vehicle crash on the New Jersey Turnpike in June 2014. ... U.S. Army veteran Noah Galloway, who lost part of an arm and leg while serving in Iraq and later was a contestant on "Dancing with the Stars," threw out the first ball. With Tanaka and players on both teams applauding, Galloway threw a strike from the mound. ... "American Idol" winner Nick Fradiani sang the national anthem.