The Gunners blew a 4-0 first-half lead to draw 4-4 at St James' Park.
"None of us wanted to look the boss in the eye," said the winger. "It was such a disappointment.
"When you are 4-0 up and want to win the league, it shouldn't happen, even if you have a man sent off.
"Newcastle taught us a lesson. They showed us how to play against 10 men. We are known for keeping the ball. On Saturday we didn't."