The 31-year-old was making his first appearance since limping off in tears during the Euro 2016 final, but was handed the perfect return on a plate by Gareth Bale as the Welshman squared for Ronaldo to tap into an unguarded net.
Transfer ban won't stop Real winning: Zidane
Despite failing to hit top gear, Real comfortably matched a club record of 15 straight La Liga wins as Danilo's low drive and a towering header from Sergio Ramos extended the lead before half-time at the Bernabeu.
The Portuguese was withdrawn to a standing ovation to make way for Karim Benzema with one eye on Wednesday's clash with his first club, Sporting Lisbon, in the Champions League.
Griezmann leads Atletico Liga lift-off
However, Real's defensive deficiencies were exposed in the second-half as Oriol Riera and David Garcia cut Osasuna's deficit, whilst Roberto Torres saw a penalty saved by Kiko Casilla.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ