CINCINNATI — Staggered by Scooter Gennett’s grand slam in the first inning, the Boston Red Sox regrouped and finally put some distance between themselves and the Yankees.

Rafael Devers hit a three-run homer Friday night, and the Red Sox extended their AL East lead to four games with a 5-4 victory over the Cincinnati Reds. Boston added to its lead with the help of the Yankees’ 8-1 loss at Toronto.

The Red Sox have won 12 of 15, keeping the Yankees at bay while moving a season-high 25 games over .500 (89-64). The Red Sox already have clinched a playoff berth and home-field advantage for the wild card game, if it would come to that. Boston has never played a wild-card game, and doesn’t want to settle for one now.

“The ball’s in our court,” said David Price (6-3). “We win, we’re fine. We don’t care what the Yankees do. We just go play our game.”

Their AL Cy Young Award winner is still struggling heading into playoff time, though.

Rick Porcello gave up Gennett’s fourth grand slam – a Reds’ season record – in the first inning. He lasted a season-low four innings, turning a 5-4 lead over to the bullpen. Porcello has lost 17 games – most in the majors – after winning 22 last year along with the Cy Young.

With the left-handed Price fresh, Manager John Farrell decided Porcello was finished after 57 pitches.

“I just felt with the left-hander in David going against the heat of the order was the move to make,” Farrell said. “I know Rick did not want to come out of that game, and I fully respect that.”

Part of Porcello’s problem has been a lack of run support. Boston has been blanked while he’s on the mound in 10 of his losses. This time, the Red Sox got him off the hook, overcoming Gennett’s career-high 27th homer with the help of Devers’ three-run shot off Sal Romano (5-7).

The Red Sox are last in the AL with 159 homers.

Price pitched 22/3 innings and contributed a single, bringing the Red Sox to the front of the dugout for a celebration. Craig Kimbrel pitched the ninth for his 34th save in 38 chances. He hasn’t allowed a run in his last 10 appearances.

NOTES: The Red Sox are 10-1 against the Reds all time in their interleague series. The Reds beat the Red Sox in seven games for the 1975 World Series championship. Overall, Boston is 14-4 in interleague play this season. The Reds are 5-13. … Farrell had lunch with his son, Luke, a Reds reliever. Luke wears the same No. 52 as his father. The last time a manager faced his son as an opposing player was 2004, when the Giants’ Felipe Alou went against his son Moises of the Cubs. Farrell didn’t get into the game Friday. “It’s definitely unique,” John Farrell said. “Hopefully it’s just a side story to a successful series for us.” … Boston left fielder Andrew Benintendi had several hundred relatives and friends cheering him from the upper deck in left. Benintendi attended Madeira High School in suburban Cincinnati and regularly attended games at Great American Ball Park. His favorite player was Ken Griffey Jr. “I just remember watching the guys play and picturing myself out there,” Benintendi said . “It’s crazy that I’m here now.” … INF Eduardo Nunez is increasing his daily workouts as he recovers from a sprained knee, but isn’t close to a full return. “We have to see some marked improvement,” Farrell said. “First thing would be a potential pinch-hit situation. We’re not going to risk anything until we get him on the base paths and get a better feel for what he’s capable of doing.”