But Webber is confident nothing dangerous occurred.
"It was OK. I knew I had Felipe there," said Webber.
"I rolled out of it a little bit to let him merge back in, and then took the fast lane."
After a gearbox-change penalty dropped him to 12th on the grid, Webber was only able to take sixth place in the race.
"Obviously the start was pretty wild, which can happen at La Source," said the Australian.
"Then we settled into a race where it became very, very obvious that it was difficult for us to overtake on track. Obviously Seb [Vettel] and I had a little fight, which was fine.
"After that you could see after Eau Rouge it was just not possible for us to fight other people in a straight line. That made it tough.
"Then we tried to under-cut some people and then you start to roll the dice.
"I had Vitaly [Petrov] on the out-lap, and fair play to him, he's doing his thing, but obviously you lose some time there.
"It just didn't line up. We had a bit of luck on the first lap but after that we didn't make the most of the situation."
The result drops Webber from second to third in the drivers' championship. He closed the gap on leader Fernando Alonso - who was taken out at the start - from 40 to 32 points, but fell behind Red Bull team-mate Vettel, whose runner-up finish brought him up to second in the standings.