NEW YORK -- The grounder was not the hardest-hit ball of the day -- not even close, because that honor belonged to Giancarlo Stanton's heat-seeking missile into the right-field seats -- but it was exactly what Josh Donaldson needed to make an impression on his first Opening Day with the Yankees.

Donaldson's 11th-inning knock bounced past a pair of diving Red Sox defenders, leaving second baseman Trevor Story rolling gloveless on Yankee Stadium's outfield grass. Isiah Kiner-Falefa slid home with the deciding run as the Bombers flashed some grit, rallying for a 6-5 victory over their archrivals.

"It was nice for my first game here, to be able to help the team win," Donaldson said. "I feel like we showed some resiliency today. We got down early on; a couple of big homers. We just kept at it, kept trying to grind down at-bats, and our bullpen kept us in the ballgame."

Donaldson is just the third Yankee since RBIs became an official stat in 1920 to record a walk-off RBI in his Yanks debut, joining Roy Weatherly (1943) and Chase Headley (2014). It was also the club's sixth walk-off win on Opening Day in franchise history (1906 vs. Red Sox, 1908 vs. Athletics, 1943 vs. Senators, 1949 vs. Senators and 1957 vs. Senators).

It was an afternoon stocked with plenty of firsts -- debuts in pinstripes for Donaldson and Kiner-Falefa, among others -- and jam-packed with storylines, from Aaron Judge turning down a contract extension before first pitch to Gleyber Torres riding the bench as the odd man out in a crowded infield mix, only to be summoned for a key pinch-hit opportunity in the 10th inning.

After two very abnormal pandemic-affected Opening Days, a sellout crowd of 46,097 savored a full return to the Bronx on this day -- perhaps one with an ounce too much pomp and circumstance, in the eyes of right-hander Gerrit Cole, who barked as pregame ceremonies (including Billy Crystal's first pitch, low and outside) ran a few minutes long.

Cole called the micro-delay "an unforeseen challenge," as was Boston's loud contact in the first inning, an unwelcome flashback to last year's American League Wild Card Game. Cole heard boos as J.D. Martinez doubled home Xander Bogaerts with the third Red Sox run, then righted himself to offer four innings and 68 pitches -- close to his limit, given the abbreviated Spring Training.

"There was a little bit of adrenaline today, especially in the first," Cole said. "It took a minute to get the sights."

The Yankees powered back, flexing the brand of muscle that Donaldson has opined should make them capable of doing "whatever we want" this season. Anthony Rizzo celebrated his return by slugging a two-run homer in his first at-bat of the year, then Stanton awed the crowd with a 116.3 mph rocket that left the playing field in 3.5 seconds.

"I said to Judge, I've watched so many Yankees games from afar, seeing a team score early but then just score right back," said Rizzo, who referenced the 2019 London Series slugfest between the rivals. "It was a nice response for us. One game could be the deciding factor in 162."

Carrying the encouraging opposite-field power he showed this spring into games that count, DJ LeMahieu homered in the eighth, even showing some emotion as he rounded the bases.

"Opening Day. Rivalry game," LeMahieu said later, stoically. "Just excited."

Torres battled encroaching shadows to lift a game-tying sacrifice fly in the 10th, earning a welcome confidence boost after manager Aaron Boone tackled the difficult task of telling the infielder he would need to sit in favor of LeMahieu.

"I'm proud of him," Boone said. "These last couple of days were probably not easy at all."

Torres' fly took reliever Michael King -- New York's eighth pitcher of the afternoon -- off the hook after King allowed a soft-contact Bogaerts single that chased home an automatic runner with the go-ahead run. King iced Boston in the top of the 11th, striking out two.

"That's the kind of thing kids dream about, especially me growing up as a Yankee fan in Red Sox territory," said King, who was born in Rhode Island and attended Boston College. "It's just a fun atmosphere in this locker room."

Donaldson was the first batter in the home half of the 11th, and he'd also be the last of the day.

"Total team win," Donaldson said. "Hopefully it'll lead to good things in the future."