Left-back Monreal joined the Gunners from Malaga on transfer deadline day in January, taking the same route to north London as Cazorla did last summer.
Cazorla has been in excellent form for his new club since his arrival while Monreal scored his the first goal in a 2-0 Premier League win at Swansea City before the international break.
"He's a very good signing, and he's proving it," Cazorla told Arsenal Player.
"Nacho is a footballer I really enjoy watching and playing with. I spent last season with him at Malaga and he was a vital player for the team. He's adapted to the Premier League very well. What's more, our style of play suits him because he's someone with a lot of movement.
"I think Arsenal have really got it right with the transfer. I'm very happy because he's a great mate.
"We know each other from Malaga and I know it can be difficult when you arrive."
Cazorla turned to another Spaniard, Mikel Arteta, for guidance when he first arrived in England and he in turn has helped Arsenal's latest signing from Spain to settle.
"We know each other from Malaga and I know it can be difficult when you first arrive," said Cazorla.
"I had the exact same experience and, thanks to Mikel, I adapted much better. So I know, for Nacho, it makes it easier to adjust if he has me and Mikel.
"We've tried to help him settle as easily as possible and, little by little, he's understanding more. He's got a feeling for the club. I talk to him every day and he's very happy to be at Arsenal."