Justin Bieber wasn't afraid to play dirty during a charity hockey game, getting in a scrap with former NHL star Jeremy Roenick ... but there's no bad blood.

On Sunday, Bieber was participating in the Skate For L.A. Strong event at Crypto.com Arena ... and the game hilariously took a turn when Biebs and Roenick duked it out in the rink.

Check out the video ... JB flips Roenick's jersey over the ex-NHLer's head and playfully fakes to uppercut his chin. Fortunately, this was all in good fun, because Bieber definitely has control!

JB and 55-year-old Roenick were eventually separated, and Biebs skated away with a big grin on his face.

Justin clearly seems in good spirits after his rep shut down social media speculation that he's been using hard drugs. Instead, the singer's rep insists he's in one of the best places in his life, -- focused on parenting and making music -- and he definitely seems happy playing hockey.

As for the hockey event ... big stars like Will Ferrell, Steve Carell, Snoop Dogg, Danny DeVito and Vince Vaughn were all in attendance.