Ronaldo headed the opening goal after 10 minutes and fired home an emphatic second 17 minutes from time, before claiming the matchball as Atletico pressed for a route back into the semi-final tie.
Ronaldo scored a hat trick to reach 400 goals with Madrid and lead the defending champions to a commanding 3-0 win over city rival Atletico Madrid in the first leg of their Champions League semifinal on Tuesday.
With 16 minutes left, Ronaldo rifled a free-kick into the net and celebrated the goal but it was clearly deflected by Portugal and Real Madrid team-mate Pepe.
Relive the top moments from Tuesday's Champions League semi-final between Real Madrid and Atletico Madrid. He scored in 20th minutes as well. The Portuguese spoke to Real Madrid television on Wednesday about his 400 goal for the club and the team's objectives.
Ronaldo became the first player to record three career hat tricks in the Champions League knockout stage, while he also went level with Lionel Messi with his seventh treble in the competition as a whole.
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Ronaldo signed a new five-year contract last November that will see him stay at Madrid until 2021, when he will be 36.
Unfortunately their team made it hard for themselves, conceding two second-half goals to the irrepressible Ronaldo, leaving themselves little hope of a dramatic comeback next week. There's still a long way to go, both in La Liga and the Champions League.
"As I've said, we have a slight advantage and we are one step closer to Cardiff".
"The players who normally play the most are arriving at the most important moments of the season feeling fresher and more focused".
"Our remaining games are like cup finals and we have to win all of them". "He is unique. All the players were brilliant", the Frenchman said.
"The squad is the key to our success, having substitutes that always make their presence felt and play as well as those of us who play more often", Ramos told reporters.
"We still have the second leg".