BUFFALO, N.Y. — It was a moment that Gavin McKenna will probably never forget.Justin Bieber, decked out in a red Team Canada jacket, striding up to the draft stage at KeyBank Center to welcome him — “Mr. McKenna” — to the Leafs while Bieber’s song “Yukon” strummed in the background.The welcomes kept coming.Moments after he pulled on a blue Leafs jersey with the No. 26 on the back, McKenna stood next to Bieber as the pop star and Leafs super fan threw to a video message, this one from the captain of the Leafs, Auston Matthews, drafted No. 1 overall himself in the very same building 10 years earlier.As predicted, Gavin McKenna goes No. 1The Athletic Hockey Show“Gavin” chants erupted from the large contingent of Leafs fans in attendance.“This isn’t what I imagined as a young kid,” said McKenna, grinning constantly, a short while later. “It’s so much better.”It was a rapturous introduction to the Leafs for someone who may end up changing the franchise.McKenna is the unexpected grand prize for one of the most disappointing and chaotic seasons in franchise history; one that started with the team hoping to contend for a Stanley Cup but ended instead with the first playoff miss in the Matthews era and the firings of general manager Brad Treliving and head coach Craig Berube.McKenna gives the Leafs a major shot of hope, for today and tomorrow.How much he can impact a team with playoff aspirations next season as a teenager is a great unknown at this point.The jump to the NHL is significant for any rookie, let alone one as small and light, if exceptionally skilled, as the 5-foot-11, 170-pound McKenna.A similarly sized Jack Hughes, the top pick in the 2019 draft, managed only seven goals and 21 points in 61 games as an 18-year-old for the New Jersey Devils before eventually blossoming into the star who scored the gold medal-winning goal for Team USA at the 2026 Olympics.Unlike Hughes, who joined a mediocre Devils team led in scoring by Kyle Palmieri’s 45 points, McKenna comes aboard a veteran Leafs squad that boasts a reasonably deep well of talent that should include Matthews, William Nylander, Darren Raddysh, Jake McCabe, John Tavares and Chris Tanev, among others.Hughes’ most frequent linemates as a rookie were Palmieri and a past-his-prime Wayne Simmonds.McKenna could get a chance to play with Matthews right away and throw alley-oops to one of the league’s top goal scorers.He wasn’t shying away from that kind of opportunity either, calling it his goal to play with “my captain.”“I’m gonna have to prove myself to be able to play with a player like that,” McKenna said. “I think my game is obviously a playmaker. He’s a shooter. I think we can complement each other pretty well.”Justin Bieber, right, was on hand to announce Gavin McKenna as the No. 1 pick. (Bruce Bennett / Getty Images)He might get an immediate shot, too, to bring some of his playmaking dynamism to a puffed up No. 1 power-play unit that figures to feature Matthews, Nylander and the big blast of Raddysh at the point.The last two No. 1 overall picks, Matthew Schaefer and Macklin Celebrini, both popped right away for the Islanders and Sharks.