Arsene Wenger says Hector Bellerin who suffered a concussion had no idea Chelsea had scored in the 13th minute.
Wenger felt Marcos Alonso’s aerial task on the defender was dangerous, as the winger arrived with pace and caught the Spain international with an arm.
Bellerin could no longer continue in the match and was substituted, as second half goals from Hazard and Fabregas won it for the Blues.
After saying at a post-match news conference his right-back was concussed, Wenger said: “Was he completely knocked out… He didn’t know the result of the game at the time. He didn’t see the goal.
“The decision [to substitute Bellerin] was, for me, very quick, but we have to respect that. It is the head.”
Wenger believes players not receiving adequate protection from officials in aerial challenges is something that needs to be addressed.
“One of the particularities of the game today is that referees are much more severe with tackles on the ground and let much more go with elbows in the face,” he said.
“It is not only today but in many, many games I see that. But it is more dangerous to hit the head than the legs.”