Reigning Ballon d'Or winner Ronaldo scored twice as two-time defending champions Madrid eased past Cypriot visitors APOEL 3-0 at the Santiago Bernabeu on Wednesday.
Still serving a five-match domestic ban for pushing a referee in the Supercopa de Espana, Ronaldo returned to the fold with a trademark brace as he took his record Champions League tally to 107 goals.
Ronaldo and Madrid have their sights firmly set on a third successive European crown.
"There's still a long way to go; let's go game by game. First we have the group stage then we can see," Ronaldo said via UEFA.com.
"We, of course, want to win this tournament. The Champions League is Real Madrid's competition and we want to win it."
The 32-year-old put Madrid ahead in the 12th minute before doubling his tally with a penalty six minutes into the second half.
Madrid captain Sergio Ramos completed the scoring when he converted an exquisite bicycle kick just past the hour-mark in the Spanish capital.
"I'm delighted to be back playing," Ronaldo said. "This is a special competition and to start playing again and scoring goals is very important for me. I helped the side and feel good about that.
"It was a game we needed to win; we played at home and wanted to start the Champions League well. I think the side were good; we know we were taking on a defensive outfit. We could've scored more but, in the end, it was a good result and we've started off well and we're happy with that."