The sight of Hector Bellerin being stretchered off the pitch against Chelsea was a hard one to take for everyone connected to the club.
It has since been confirmed that the Spain international will miss between six and nine months after rupturing the anterior cruciate ligament of his left knee.
But Unai Emery is backing Bellerin to come back stronger.
"Yes, we were sad and we are sad now after his injury," Emery said. "I think this year is very difficult for big injuries like Hector, Rob Holding and Welbeck.
"But football is like that.