Marcelo was also on target for the Spanish giants, while his fellow Brazilian Ramires offered a solitary reply for the Blues.
A contest played at the home of NFL franchise the Miami Dolphins saw Ronaldo return to haunt former Real boss Jose Mourinho - who was facing the club he left at the end of last season for the first time since bidding farewell to La Liga.
The game also saw Real coach Carlo Ancelotti facing familiar foes, with the Italian tactician getting one over on the side he guided to a Premier League and FA Cup double in 2009/10.
It took just 13 minutes for Los Blancos to open the scoring in Florida, with Ronaldo slipping in Marcelo to neatly step inside his marker and drill low into the bottom corner.
Chelsea responded almost immediately, with Ramires racing clear to calmly flick the ball over the onrushing Iker Casillas.
Real were back in front, though, just past the half-hour mark, with Ronaldo crashing home a trademark 25-yard free-kick which Petr Cech could only get fingertips to.
The game remained evenly poised at the start of the second half, and Eden Hazard spurned the best of several chances created by Mourinho's Blues.
It was, however, to be Ronaldo who had the final say on 56 minutes as he timed a run into the box perfectly to steer home a close-range header and get Real's hands on pre-season silverware.