The Celtics must be more aggressive going to the rim.
"We also have gotten [to the rim] and gone away from the contact to try to finish the basket instead of going through," said Rivers. "I think we all saw that. We did drive. But we drove and tried to make some crazy shot instead of going through bodies.
"It's a matter of driving with force and playing with force. It's not just the word hustle. I think it's a lot deeper than that."
Boston has failed to convert on a number of scoring opportunities around the rim.