Mitchell set a Cleveland record with 71 points, most by an NBA player in 17 years, and the Cavaliers rallied from 21 down to beat the Chicago Bulls 145-134 in overtime Monday night.
It was the most points in a game by any player since Los Angeles Lakers legend Kobe Bryant had 81 against Toronto on Jan. 22, 2006.
Wilt Chamberlain owns the NBA record with 100 for Philadelphia against New York on March 2, 1962, at Hershey, Pennsylvania.
"To be there in the record book with guys like Wilt is truly humbling,'' said Mitchell, who was acquired from Utah in the offseason.
"I always believed I could be one of the best players in the league. I'm speechless and blessed to be in the company of that greatness.''