Reds' boss Richie Barker dropped Alexander for the first time this season following the striker's goal drought which has now spanned 13 matches.
"I think Gary needed a bit of help. He needed to be taken out of the situation, and you could see it in training on Friday, it was like a big weight had been taken off his shoulders," Barker told the Crawley Observer.
"I had the conversation and you could see there was a bit of relief in his face. He was banging them in during training, it was like the world had been lifted off his shoulders."
Barker, a former striker himself, sympathised with his captain and admitted his decision was partly formed by his own experience of going 14 games without a goal.
He added: "I look back and I wanted someone to make the decision for me. He agreed with my decision and said he had been waiting for me to do it. He will get his chance again. He has worked extremely hard."