The Portuguese superstar scored late on to salvage a vital point for United in the group stage clash with the Italian side and has called on his teammates to step up following the lucky escape.
Ronaldo told BT Sport: "It was a difficult game. I know that when we play Atalanta it's difficult and we believe until the end that I will help my team get the three points and I'm so happy. We never give up and believe until the end. It’s a good result for us I think.
"The beginning was tough, Atalanta have a fantastic coach and they know what to do. I knew when I played in Juventus. We did our job well. We are lucky I scored but that's football.
"We still have to improve. We have different players and different systems. We have to adapt but it will take time. We have time to improve."
It is the third consecutive Champions League game that Ronaldo has made the difference for United and manager Ole Gunnar Solskjaer likened him to NBA legend Michael Jordan.
The coach said: "We all have our roles and responsibilities. Of course Cristiano is a leader in the group but that's what he does, he scores goals.
"We're not happy conceding two goals - but he does provide those moments and I'm sure the Chicago Bulls didn't mind having Michael Jordan either.
"Sometimes teams have the players they have and that's why they are Manchester United, that's why they are champions at the Chicago Bulls. You just come up with those moments."