Real Madrid took another huge step towards becoming the first club to retain the Champions League with a convincing first leg semi-final victory over local rivals Atletico Madrid.

Cristiano Ronaldo grabbed many of the headlines for scoring his 47th career hat-trick but there wasn't a single Los Blancos player who didn't have a good game at the Bernabeu.

Of course, there is still a second leg to play next week and Zinedine Zidane was eager not to encourage any complacency from his players after the 3-0 win.

"We had a great game, but there is another one still to come. We scored three goals and kept a clean sheet, but there’s still a return leg," the Madrid boss said, as per AS.

"Until the referee blows the final whistle, you never know what might happen. We can be happy because the guys played really well. I’m very proud of all of them.”

Zidane's men - and Ronaldo in particular - were dominant from the very first whistle against an Atletico side that are traditionally very tough to beat.

But Madrid took control of the tie when Ronaldo headed home a Casemiro cross from the right with less than 10 minutes on the clock.

However, replays appeared to show the Portuguese international was actually stood in an offside position during the previous phase of play which saw Sergio Ramos deliver a cross Atletico could only half-clear.

As you can see below, Ronaldo is stood beyond the last Atleti defender but whether he is actually interfering in play is still up for debate.

It was one of the big talking points at half-time and the controversy appeared to filter down to the Madrid dressing room too.

Spanish TV channel Mega have captured a moment inside the tunnel at the Bernabeu when Ronaldo approached English referee Martin Atkinson during the interval.

In the still images below, what Ronaldo says translates to: "Atkinson, offside? Did you not see? I did not interfere…"

By that point, of course, the goal had already been awarded so what Ronaldo was trying to achieve by talking to Atkinson is unclear.

Anyway, he managed to add a second by hitting a thunderous half-volley from the edge of the box in the 73rd minute before completing his hat-trick with four minutes of normal play to spare.

Ronaldo has now scored 103 Champions League goals and 52 in the knockout stages. And his critics still claim he doesn't do it on the big occasions...