Isaiah Thomas is performing brilliantly on the court in the Celtics' first-round playoff series against the Bulls, but that doesn't mean he's not struggling on the inside.

Thomas expressed his feelings while addressing the media after the Celtics tied the series at 2-2 with a 104-96 victory Sunday. It was the first time Thomas had spoken to reporters since his younger sister, Chyna, died in a car accident on April 15, a day before the series began.

"Mentally and emotionally, I'm not here, so I just feed off what the guys give me," Thomas said. "They give me a lot of confidence. I can't do it without those guys. They believe in me. Being here is what makes me, I guess, sane. It makes me feel somewhat normal through this tough time."

Thomas turned in his best performance of the series in Game 4, taking over for stretches in both the third and fourth quarters en route to 33 points and seven assists. For the series, the All-Star is averaging 25.5 points and six assists.

Thomas and the Celtics will look to take control of the series during Wednesday's Game 5 in Boston.