Wenger said the Colombian, who made an error in Arsenal's Champions League defeat by Olympiakos Piraeus last season, has silenced his critics.
"He showed his detractors, those who doubted him, that he is a very good goalkeeper. Last year he made a mistake in the Champions League and everyone jumped all over him," Wenger told British media.
"On what he delivered, he has the right to stay in the team for the next Champions League game."
Ospina played just four league games last season, with Petr Cech the first-choice in goal since joining from Chelsea last June.
Wenger expected Ospina to feature more for the club this season.
"He showed what he's about. I have two world-class goalkeepers. I can give them both games. If they do not play, you can't keep two world-class goalkeepers. We have a rule that the keepers know," Wenger added.
"It's important to have clear rules like that. They know what the rules are for the season. It's down to performances."
Arsenal will host Basel on Sept. 28 in their next Group A Champions League game.
(Fixes Ospina spelling in headline and para 2 and 6.)
(Reporting by Ian Rodricks in Bengaluru; editing by Amlan Chakraborty)
