The 26-year-old arrived from Malaga on transfer deadline day and made his Gunners debut less than 48 hours later.
Monreal replaced the injured Kieran Gibbs at left-back and helped his new team-mates to a hard-fought 1-0 victory.
The Spain international put in a convincing performance at the Emirates Stadium and Wenger believes it bodes well for the future.
"We are a team who can create chances and score goals," the Frenchman said. "Against Stoke it was not the case; we created chances but could not get the goals.
"But still I am happy that we didn't concede and the defence looked solid.
"The satisfaction is that Nacho Monreal had a good start for a player who just arrived yesterday and is in the team.
"He did not have time to think about it, but he got stronger and stronger during the game.
"There is no better culture shock than Stoke when you come from Spain! They had a very physical game and I think he dealt well with it."
Wenger was also pleased by the way Theo Walcott dealt with the attention he received on Saturday.
"There were some heated moments," Wenger added. "I don't think there was anything exceptional in the tackles.
"Theo Walcott got good treatment today, but I am very happy because the way he responded to it was with full commitment and desire to impose himself.
"That is where you see that Walcott has become a different player recently.
"They know that we try to play a game based on movement and technique and they oppose us with a very strong defence.
"You have to give them credit for the way they defended today, but overall I don't think too much happened. Apart from Theo Walcott, he got a few bad tackles that maybe deserved a yellow.
"Overall it was a physical game with a team who tries to get some points and we expected that. We prepared mentally for that."
It was a result that could have been a whole lot worse for Stoke had it not been for the heroics of goalkeeper Asmir Begovic.
The 25-year-old proved why he is so sought after with a fine first-half display in which he superbly denied Alex Oxlade-Chamberlain either side of stopping a Laurent Koscielny header.
Begovic was eventually beaten by Lukas Podolski's deflected free-kick but his performance, coupled with Birmingham goalkeeper Jack Butland's deadline-day acquisition, has led to suggestion he could leave the Britannia Stadium this summer.
"He is a top goalkeeper and he made some fantastic saves," City boss Tony Pulis said. "We have hopefully signed another fantastic young goalkeeper in Jack Butland.
"The speculation will now be about Asmir but we never bought Butland [to replace him]. We bought Butland because we thought it was a fantastic deal for a kid who hopefully has a great future in front of him."