Real Madrid's hopes of beating Barca to domestic glory ended last weekend, but that did not stop Carlo Ancelotti's men from starting in style Saturday, with Marcelo's inch-perfect cross met by the head of Ronaldo 13 minutes in to make it 1-0.
But the visitors scored twice in a matter of minutes to take the lead, before Ronaldo scored a free kick to put his side back on level terms and equal his previous best total of 60 goals in a season dating back to the 2011-12 campaign.
That personal record was broken two minutes later when the 30-year-old converted a penalty to put the Blancos 3-2 in front at the Santiago Bernabeu — his 313th goal in his 300th game for the club.
Ronaldo's hat trick means he now has 48 league goals this season, which makes him the top scorer in the major European leagues in 2014-15 and a three-time Pichichi winner. He is also just 10 goals behind Raul as he closes in on becoming Madrid's all-time leading scorer.