Cristiano Ronaldo is the greatest player in the history of the Champions League.

Say what you like about the constant comparisons with Lionel Messi, but there can be no denying who the top dog is when it comes to Europe's premier competition and his name is Ronaldo.

The Juventus superstar is chasing a Champions League triumph with his third club, having won in 2008 with Manchester United and collected four trophies in five seasons at Real Madrid.

Ronaldo's European greatness

Ronaldo is the highest goalscorer in the competition's history with a staggering 128 goals, which puts him clear of his Barcelona rival by a comfortable 14 strikes.

Combine that with the fact he's scored in three finals, has bagged the joint-most hat-tricks and holds the record for most goals in a single Champions League to truly understand the point we're getting at.

So, although Juventus currently trail 1-0 on aggregate against Lyon in this season's round of 16, it's no surprise that so many supporters are backing Ronaldo to help them turn things around.

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The Champions League GOAT

Besides, it would put his GOAT status in the competition well and truly beyond doubt if he can match Clarence Seedorf's achievements of bringing 'Big Ears' back to three different European giants.

And if you're looking forward to Ronaldo potentially producing even more greatness on Friday night, we though we'd set the scene here at GIVEMESPORT by digging deep into the Ronaldo archives.

Here are the 11 greatest Ronaldo moments that prove, for us at least, that the Champions League has never played host to a greater player: 

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1. Breakout performance vs AS Roma

It's astonishing to think, considering Ronaldo's greatness in this competition, that it took him until his fourth season at United to score in the Champions League proper, but what a way to break your duck.

This was a memorable night for the Red Devils all round as they put their Italian rivals to the sword 7-1 and Ronaldo was at the heart of things with a brilliant brace, the first goal of which was a very classy strike.

2. Masterclass in 2008 Champions League final

You'd be forgiven for thinking that Ronaldo's performance in Moscow was a little mixed when you consider he scored a glorious header, only to almost cost United by missing in the shootout.

However, that simply wasn't the case with Ronaldo playing just about every Chelsea player off the park, dropping the sort of step-overs and skills on the flank that we've come to miss in recent years.

You can check out his full individual highlights down below to really bask in his masterclass:

3. Puskas Award winner vs Porto

Ronaldo has always had an eye for a spectacular goal, particularly during his United days, so it should hardly surprise us that the Portuguese was the first ever recipient of the Puskas Award.

And trust Ronaldo to achieve it on the Champions League stage, sending an absolute rip-roarer of a strike into the top corner and past Helton with only the choppy camerawork putting a dampener on it.

4. THAT free-kick against Arsenal

From one incredible goal to another and frankly, we could have put down Ronaldo's display in general considering he bagged a brace at the Emirates and looked head and shoulders above this Arsenal side.

But there's no denying that the highlight came when he baffled everybody to score a free-kick from fully 40 yards with Clive Tyldesley even saying just beforehand: "Too far for Ronaldo to think about it."

Yeh, about that.

5. 17-goal Champions League season

It wasn't until later in Ronaldo's Real spell that the success started to flow in the Champions League, so we're skipping ahead to the 2013/14 season, but with one of his greatest ever achievements.

Most top European strikers would be happy with 17 goals in all competitions, so the fact Ronaldo achieved that in the Champions League alone is still beggar belief.

The Portuguese scored a staggering nine goals in the group stages, seven in the knockout rounds and then capped off 'La Decima' by converting the fourth goal in the final against Atletico Madrid.

6. Hat-trick comeback from 2-0 down

This title could look very familiar, very quickly, but the first time Ronaldo executed a major rescue mission in the Champions League came in 2015/16 after a 2-0 first-leg defeat to Wolfsburg.

That all came unravelling in Ronaldo's back garden, though, as the Portuguese levelled the scores in 84 first-half seconds, before completing the turnaround with a trademark knuckle-ball free-kick.

7. Penalty shootout winner in the final

One of the compliments most regularly paid to Ronaldo concerns his calmness under pressure and walking from the half-time to take a Champions League-deciding penalty is the ultimate nerve-wracked.

But this is Ronaldo we're talking about and the Real legend is truly prolific from the spot - take from that what you will - showing nerves of steel to once again dish out heartbreak for Atletico.

8. FIVE goals vs Bayern Munich

What Ronaldo achieved during the 2016/17 knockout stages isn't discussed enough - scoring three goals against Jan Oblak, five past Manuel Neuer and two against a 'keeper we'll talk about next.

But back to Neuer and Bayern for one second because the fact Ronaldo managed to notch up two goals at the Allianz Arena and then a hat-trick in front of his own fans is simply otherworldly.

9. Brace in the final vs Juventus

It's simply a fallacy to say that Ronaldo doesn't shine in Champions League finals, give or take 2018, so lest we forget that he was in fine goal-scoring form against a top Juventus team in Cardiff.

And just because neither of his goals quite compared to Mario Mandzukic's bicycle kick, it doesn't mean that his predatory instincts to beat Gianluigi Buffon twice should be any less appreciated.

10. THAT bicycle kick against Juventus

The greatest goal that Ronaldo has ever scored in his Champions League career.

It's no wonder that the five-time Ballon d'Or winner wanted to move to Juventus when the whole stadium applauded him for levitating in the air, acrobatically volleying the ball and duly finding the net.

11. Comeback hat-trick vs Atletico Madrid

To tell you the truth, Ronaldo hasn't given Juventus fans too much in the way of spectacular Champions League memories yet, but the one he has delivered for them is one for the ages.

It's one thing to instigate a comeback from 2-0 down against Wolfsburg, yet it's an entirely different thing to achieve that against an Atletico side that is world-renowned for its defending.

That meant nothing to Ronaldo, though, as he levelled the scores with two all-conquering headers and then propelled Turin into the stratosphere by completing his hat-trick from the penalty spot.

GIVEMESPORT's Kobe Tong says

If some of those moments didn't give you goosebumps then you're simply not human.

I'll be the first person to admit that I don't think Juventus will win the Champions League this season, but if they do, then I already know that Ronaldo will have a massive say in things.

And although Messi has actually outdone him in Europe so far in 2019/20, I don't doubt for a second that Ronaldo will raise his game in the biggest fixtures like he always does.

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Lyon are one of the weakest teams left in the competition, sure, but coming back from 1-0 without an away goal shouldn't be taken for granted and Ronaldo will need to dig deep for glory again.

However, even if Juventus were absolutely trashed 5-0 on Friday, their star man has already done enough to boast GOAT status in the Champions League for now.

Bringing that coveted trophy to the Allianz Stadium, though, would put the title out of Messi's reach forever.

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