Real Madrid and Paris Saint-Germain served up a memorable clash in the first leg of their last-16 Champions League tie last night.
On an occasion that's become very rare over the last decade or so, PSG actually arrived at the Bernabeu as favourites to beat their hosts.
And it was easy to see why. The French side are 12 points clear in Ligue 1 and have lost only two domestic games this season.
Madrid, in comparison, have been stuttering.
They're sitting fourth in La Liga, 17 points behind leaders Barcelona and qualified for the knockout round of the Champions League after finishing second in their group.
But when the pressure was on, Zinedine Zidane's side stepped up on a huge night and beat PSG - who were favourites to win the competition, 3-1.
Cristiano Ronaldo silenced his critics with a brace, cancelling out Adrian Rabiot's opener with a penalty before scoring again in the last 10 minutes.
Marcelo rounded off the scoring moments after Ronaldo made it 2-1, completing a very impressive comeback that puts Real in good shape heading into the second leg.
Although the result has not been questioned - Madrid fully deserved the win, there has been some debate over Ronaldo's penalty.
On first looks, there was nothing wrong with the spot kick. Ronaldo didn't stutter in his run-up and there were no other players in the box when he hit it, so it all looked good.
But upon closer looks, it seems that the Portuguese did something very special with his penalty.
Zoomed, slow-motion replays appear to show that Ronaldo was able to make the ball jump off the spot when he planted his left foot, before striking it clean with his right.
It's quite a technique, one that's probably never been seen before and one that's incredibly hard to spot in real time.
But according to former Premier League referee Graham Poll, the penalty should not have stood. And if last night's referee had seen it, Ronaldo should have been made to retake the kick.
Why? That's something that Poll explains very clearly.
"You cannot blame the officials for missing it, as it would have been almost impossible to spot in real time," he said, per the Mirror.
"But with the benefit of slow-motion replays, we can see that the ball bobbled up as Ronaldo planted his left foot, before slamming it home with his right.
"The ball must be stationary when a penalty is struck so, had the referee spotted it, the kick would have been retaken."
Of course, nobody's blaming the referee for missing it last night. But, now that his technique has been found out, Ronaldo may not be able to use it again, for the reason Poll suggests.
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