A double-technical was called on Gibson and Brand.
The play happened in front of the Bulls' bench, and Joakim Noah, who was in street clothes nursing a sprained ankle, tried to help separate the players.
"A highly physical game," Brand said.
Philly center Spencer Hawes said the Sixers can play a physical brand, but coach Doug Collins said they'll remain true to their identity.
"We're not a big, physical team," Collins said. "We can't play out of character and go play smash-mouth basketball. You can't let one game get you going in the wrong direction
For his part, Gibson downplayed the incident.
"It was nothing," Gibson said. "It's playoff basketball. It's us going hard. It's players playing hard for their teams. I got a lot of respect for Elton Brand. It's about playoff basketball. There's no hard feelings."