Gregorius drove in a career-high six runs, McCann hit a three-run homer in his return to Atlanta and the Yankees shook off a scoring slump to beat the Braves 15-4 on Friday night.
The Yankees scored a total of seven runs in losing three of their last four games to fall 1 1/2 games behind first-place Toronto in the AL East. They scored nine runs in just the first two innings against the Braves.
"This was a big night for us," Yankees manager Joe Girardi said. "It just shows you everyone is capable of producing in this lineup."
Gregorius had four hits, including a three-run homer in the first inning and a two-run single in the second. McCann, the former longtime Braves catcher, added his three-run homer in the eighth.
"Tonight was huge," McCann said. "You play so many games in a long season, everybody goes through slumps. Over the long haul, I really like this lineup."
Gregorius set his previous career high when he drove in four runs at Texas on July 27.
Masahiro Tanaka (10-6) allowed three runs and five hits in seven innings.
Atlanta's Freddie Freeman drove in two runs with two hits, including a third-inning homer.
Braves outfielder Jonny Gomes, making his first career appearance as a pitcher, gave up two runs in the ninth, including a homer to Chris Young leading off the inning. Gomes raised his arm in celebration and raced to the dugout after striking out pitcher Bryan Mitchell to end the inning.
McCann, who played his first nine seasons with the Braves, received a warm ovation before his first at-bat in his return to Atlanta. He tipped his helmet to the fans. He had three walks and drove in four runs.
The Yankees led 9-2 after two innings despite having their first two batters retired in each inning.
Following Chase Headley's two-run, ground-rule double that bounced over the wall in center field, Gregorius hit a three-run homer into the seats in right for a 5-0 lead in the first.
Freeman had a run-scoring single in Atlanta's two-run first inning that would have been bigger if not for Jacoby Ellsbury's inning-ending catch in deep center field. Running with his back to the infield, Ellsbury reached up to catch Christian Bethancourt's two-out drive with two runners on base before sliding on the warning track.
"That saved me," Tanaka said through a translator.
Ellsbury's status for the game had been in doubt due to a hip injury.
Williams Perez (4-5) gave up eight runs in 1 2/3 innings. It is the fifth time in his last six starts he has allowed four or more runs. Perez and Detwiler combined to issue six walks in the first two innings.
Mitchell, reinstated from the seven-day concussion disabled list before the game, gave up a run-scoring single to Bethancourt in the ninth.
COME SEE THE YANKEES
Attendance was 35,546, including a strong turnout by Yankees fans. Many sat behind the visitor's dugout on the third-base line. That topped the three-game total of 29,621 for the Braves' series against Colorado this week.
BACK TO THE MINORS
Yankees: LHP Chris Capuano, who was designated for assignment on Wednesday, was sent outright to Triple-A Scranton/Wilkes-Barre.
Yankees: 1B Mark Teixeira (bruised right shin) did not start as had been expected as he was still unable to run. Girardi said after the game the medical staff decided against more tests. "He's just got to heal," Girardi said.
Braves: INF Hector Olivera could be recalled from Triple-A Gwinnett on Tuesday, when rosters can be expanded. The Braves felt Olivera, from Cuba, needed to reach playing form following his July 30 trade from the Dodgers because a hamstring injury has limited his at-bats this season.
Yankees: Rookie RHP Luis Severino will make his fifth career start one week after earning his first win against Cleveland. He has lasted at least five innings and allowed no more than three runs in each of his first four starts.
Braves: Rookie RHP Matt Wisler will try to end a streak of three straight losing decisions. He allowed seven runs in two of those three losses -- at Philadelphia on Aug. 1, and at the Cubs on Sunday.
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