Arsenal boss Arsene Wenger is delighted with the impact of Yaya Sanogo.
The French striker has started the last two matches, against Liverpool and Bayern Munich, and Wenger believes he is starting to show his potential.
"When I first knew of him, he had not played. He had been out for two-and-a-half years," the manager said. "At 16 years of age he was a very promising striker.
"He started to play a little bit at Auxerre last year and I got alerted by [scout Gilles] Grimandi that he was playing again so I sent him to watch him. He said he could be interesting.
"Then I met him and we had a long chat about what happened to him and I decided to try to take him. He called me back and said, 'Look, I will join you'. He had had one or two more offers in France and I knew it was a going to be a building process of six months.
"In pre-season I saw he was under-strength and not ready muscularly. We decided to take him completely out and try to build him up for four months - two months in France and two months with us. When he came back on January 1, I saw he was a different animal."
