Sanchez's goal against City saw him take his tally for 2016-17 to 24 goals in all competitions but Wenger concedes his star man can take a while to get going.
"It is strange because I feel that he always grows during the game," Wenger said at a media conference.
"The difficulty of the game always makes him more focused. He starts sometimes and has problems to get into the game and during the game he becomes stronger and stronger and more determined.
"I think he adapts to the difficulty. He tests and he finds the way himself during the game to become dangerous.
"He has been remarkably efficient. I felt that he had a very good spell when he played up front. When he plays on the flank, he is more a provider than a goalscorer. At the moment he plays in a mixed role between the flank and the middle.
"He can always turn up with something special in the game. He has the individual quality to make the difference."