Real Madrid have earned a crucial advantage in their Champions League last-16 tie with Schalke 04 thanks to a 2-0 win in the first leg in Gelsenkirchen.

It was a promising start for Schalke, who frustrated the holders with their defensive play in the early stages as Roberto Di Matteo's decision to start with a 5-3-2 looked to be vindicated.

Schalke had chances to break the deadlock before falling behind, with Dennis Aogo firing over from the edge of the box before Klaas-Jan Huntelaar forced Iker Casillas into a fine save with a powerful low strike.

However, the hosts were left disappointed when Dani Carvajal was allowed time on the wing to deliver a cross for Cristiano Ronaldo, who headed past Timon Wellenreuther from close range.

Toni Kroos then created a chance with a clever pass into the path of Karim Benzema, but Wellenreturher responded well by keeping the ball out with his feet.

Ronaldo had been kept quiet in the early stages, but the goal brought him to the forefront of the game, and he tested Wellenreuther with a swerving free kick from 25 yards.

Carlo Ancelotti's side were in control when the two sides returned after the break, and Schalke struggled to pose an attacking threat without Huntelaar, who was forced off with an injury late in the first half.

Despite trailing Schalke were reluctant to make too many risks, and they almost fell further behind when Isco linked up with Gareth Bale on the edge of the box before sending a shot just over the crossbar.

Real were given a big scare heading into the closing stages when Felix Platte, who had replaced Huntelaar, rattled the crossbar with a fine strike from the edge of the box before Atsuto Uchida miscued the rebound straight to a relieved Casillas.

It was left to Marcelo to find a vital second away goal in spectacular fashion as the Brazilian cuts inside from the left wing before picking out the top corner with an unstoppable strike to edge his side closer to another quarter-final appearance.