The 29-year-old France goalkeeper has had to play second fiddle to the Tottenham star for much of his international career.
The Marseille stopper put in a solid performance during the 2-1 win in Paris, and was only beaten by a Ricardo Quaresma penalty in the last quarter of an hour.
The 29-year-old had shone earlier on in the game by denying Ronaldo with a sensational diving save to his right, with the former Manchester United ace having connected with a bullet header that looked destined for the back of the net.
But he may have only turned out against Portugal because of a slight injury to Tottenham's Lloris, France's skipper and a player in fine form in the Premier League.
"It's good for my confidence and good for the team," Mandanda told L'Equipe when discussing the result.
The goalkeeper, who was winning just his 17th cap, was also interviewed for the Fifa website, addressing how important it was to him to feature after missing the World Cup in Brazil.
"We have carried on our good run and beaten a good footballing nation, and we need to continue in the same vein," he said.
"It was a source of great pride for me to be in goal today as I'd not played for quite some time. I am really pleased from a personal point of view and from a collective standpoint, as we won.
"There are matches which go well for you and today's was one of those matches for me – I'm pleased with the save I made from Cristiano Ronaldo at 1-0.
"I am happy as things haven't always been easy for me when it comes to the national team."
Didier Deschamps will now have to decide whether Les Bleus captain Hugo Lloris is fit enough to face Armenia on Tuesday, or whether he will reward Mandanda with another cap to add to his collection.