Felix left Chelsea for Al-Nassr a fortnight ago with many inside Portuguese football disappointed with his choice.
But Jorge Jesus, after a friendly win against Rio Ave, told Canal 11: "Cristiano is a phenomenon. This stadium was full just for him; without him, there would have been no one there. The effect he has on young players is impressive. He doesn't need many chances to score: today he had three. He wanted to leave the penalty to (Sadio) Mané, but then he decided to take the second.
"Even though they've known each other for a long time, they now play more in tandem with each other. João has grown a lot physically, tactically, and technically. He's finding his footing, like all of us."
The coach also revealed the background to the arrival of the former AC Milan, Barcelona, Atlético, and Chelsea attacker: "Last year, when I was at Al Hilal, I tried to sign him. He didn't accept.
"This year, I called him straight away, and a month later, he arrived. He made the right choice: either you play here, or you play. No nightlife, no distractions."