"I didn't see what happened behind me and can't comment on the decision", said the Dutch rider who also won Friday's seventh stage to join Sagan and Gaviria with two wins each from the first eight days' racing.
Van Avermaet finished the stage second and increased his overall tour lead by more than 30 seconds.
Degenkolb was forced to lead out the sprint but the German had enough power to hold off Van Avemaet and Lampaert and claim his first Tour stage victory.
"I was following good wheels but it was choppy".
This is the second huge moment for Degenkolb in this city, after winning Paris-Roubaix in 2015.
"It was a pretty hectic day", Van Avermaet said after the dust settled. "I am very happy with my team".
Both Team Sky riders finished in the front group, 27 second behind stage victor John Degenkolb (Trek-Segafredo) with most of their overall rivals.
"I had a little tumble halfway through, but I'm just grateful to get through the stage without having any major issue", he said, aware that most of his rivals finished on the same time but that Richie Porte crashed out after just 10km.
"I'm not 100 per cent sure we should be putting cobbled stages in the Tour de France", he said.
Van Avermaet's teammate Tejay van Garderen and Frenchman Julian Alaphilippe of Quick-Step are five and six seconds back respectively. Thomas lies second on the general classification, 43 seconds behind Van Avermaet.
BMC Racing Team rider Richie Porte (C) receives medical assistance after crashing with Lotto Soudal team rider Jens Keukeleire (L) of Belgium.
Monday is this Tour's first rest day, with riders back in action on Tuesday in a 158.5km stage from Annecy to Le Grand-Bornand, marking the first of three stages in the Alps.
"I've had bad luck, but I always had the will to come back to my best".
Questions will be asked about the leadership issue at Sky after Geraint Thomas abandoned Froome when a mechanical failure saw the four-time victor crash late on.