Real Madrid were held to a 1-1 draw by Manchester United in the first leg of their Champions League last 16 tie at the Santiago Bernabeu.
Danny Welbeck opened the scoring for the Premier League leaders with a 20th minute header to deliver United a crucial away goal.
Ronaldo equalised with a header of his own 10 minutes later to set up a finely balanced second leg when Real travel to Old Trafford on March 5.
Ronaldo came up against United for the first time since leaving for the capital club in 2009, but he could not find a second goal as the Spanish giants’ prospects of a landmark 10th European title were dented.
Robin van Persie almost made it a perfect night for Sir Alex Ferguson’s side 18 minutes from time but was denied twice in matter of seconds – first by the crossbar and then Xabi Alonso’s goalline clearance.
United boss Sir Alex Ferguson made his intentions clear by fielding an attacking quartet of Van Persie, Welbeck, Wayne Rooney and Shinji Kagawa while captain Nemanja Vidic was rested from the squad entirely as he recovers from a knee injury.
Real Madrid sprung no surprises in their starting line-up, with French defender Raphael Varane replacing Pepe at centre-back and Mourinho picking his first-choice midfield and attack.
Real maintained their impetus after the break and De Gea was in action again with an athletic stop at the far post to block Coentrao once more.
Real continued to press hard but De Gea rescued United again with 11 minutes left, diving away to his right to clutch Sami Khedira’s effort.
In the dying minutes of the match, Van Persie had one more chance to snatch a win for but his angled drive was touched to safety by Lopez.