The full-back was signed from Feyenoord last month and made his bow on Tuesday, playing 55 minutes in the club's 2-2 pre-season draw with Huddersfield Town.
Despite the match being Janmaat's first since the Netherlands' third-place play-off at the World Cup, Pardew is confident the Dutchman will be ready for the visit of the champions on August 17.
"He is a class act. He will play for us against Man City there is no doubt about that," said Pardew, whose side tackle Real Sociedad in their final friendly fixture on August 10.
"He is fit and injury free. He's had 60 minutes tonight and hopefully he will get 80 on Sunday."