The Portuguese attacker scored a superb header to ensure Real Madrid shared the spoils in their 1-1 draw with Manchester United on Wednesday night, and has carried over his fine from last year into 2012.
Del Bosque, a former Blancos boss, believes the Champions League last 16 tie is finely poised heading into the second leg in early March at Old Trafford.
"The tie [between Real Madrid and Manchester United] is open,” he told reporters at the unveiling of his wax figurine at the Madrid Wax Museum.
“Real Madrid have a great team that are capable of anything, and there are still possibilities. Moreover, Cristiano is playing very well; he is at his best."
Danny Welbeck’s header had put Sir Alex Ferguson’s side 1-0 ahead but Ronaldo’s goal left the tie level heading into the second leg on March 5.
The Champions League will be a key competition for Madrid this season as they sit third in La Liga with no realistic hope of catching Barcelona, though they have reached the semi-finals of the Copa del Rey.