Isaiah Thomas just put up arguably one of the best performances of the NBA season Tuesday night when he went off for 53 points against the Washington Wizards (29 of them coming from behind in the 4th & OT) at home to take a 2-0 lead in the series with a 129-119 victory. To make the performance even greater, Isaiah did all this with a heavy heart as Tuesday would've marked his late sister’s 23rd birthday.

Following the game, TNT asked Isaiah where his intensity and performance came from, he responded emotionally “my sister. Everything I do is for her, and she's watching over me." Thomas later told TNT that his sister wouldn't want him to stop playing, and that's what drives him. 

In addition, Isaiah is the only Celtics player in history to have a 50-point game in both the regular season and the playoffs in same season.

"He was not feeling good and was having a tough day," Celtics coach Brad Stevens said after the game. "I thought he was really going to have to gut this one out. He not only guts it out, he ends up with 50.”

Check out some of Isaiah’s pos game interviews & quotes (below).