Celtics head coach Brad Stevens weighed in on Thomas' outing, per Chris Forsberg of ESPN.com: "[Thomas] was incredible. He's an amazing, amazing player. Amazing person. ... I couldn't help but be inspired by his play."
Teammate Al Horford talked about the difficulties of the circumstances: "We're never going to make excuses, but this is hard. This was difficult, and I felt like our guys really dealt with it best. We knew (Thomas) was hurting...we have a lot of respect for him that he was able to come out."
Forsberg noted Thomas was crying during pregame ceremonies when he was the last Celtic starter introduced and surrounded by teammates.
Still, he responded with 13 first-quarter points, and the TD Garden crowd provided support with a rousing ovation, as Bill Simmons of The Ringer shared:
Thomas had messages of love for his sister on his shoes, per ESPN:
Boston guard Avery Bradley also discussed Thomas' ability to play through the pain, per Forsberg: "It says a lot. Isaiah, to me, is like family. We grew up in the same area. I know it's tough for him. It says a lot about him. He's a true competitor and tonight he was playing for his sister and he was playing for his family."
On the other side, Jimmy Butler led the Bulls to victory with 30 points but was quick to show support for the Celtics guard: "He's a hell of a player. It just goes to show the type of player and man he is to go out there and battle through what he was going through for his organization and team."
Game 2 of the series is Tuesday in Boston.