The Spanish striker made his debut for the Gunners in the 2-1 win over Southampton, but Wenger thinks it will take the 28-year-old some time to adjust to the rigours of Premier League football.
"I hope so," said Wenger when asked if he expects Perez to score goals this season. "I think he got 17 goals last year.
'In the second half, I think he combined much better. It is not easy as well to start at home, the pressure is there for everybody and everybody has their eyes on them.
"You could see that especially with Mustafi, because in the second half he was much more comfortable than in the first.
"Let's give [Lucas] time. We have scored goals since the start of the season, but we bought one more striker because we thought we needed one more let's give him time and not judge him too quickly."