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Finally, it's back! The Champions League returns this week with its prestigious knockout stages, pitting the continent's best clubs against one another in gripping, two-legged ties.

This is football's golden standard, its biggest domestic stage, the competition that decides and defines legends.

To preview its return, we've analysed each of the 16 teams left and ranked them in order of how likely they are to lift the trophy come May.

Think of it as a health check ahead of the knockouts commencing, with form, fitness, ability and round-of-16 matchup all factored in. There's a clear No. 1, a gaggle of four or five clear contenders...and big old pile of pretenders—eight of which we'll say goodbye to over the next few weeks.

16. Lyon

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In the space of one regrettable December week, Lyon lost star attacker Memphis Depay and emerging midfielder Jeff Reine-Adelaide to severe knee injuries and drew Juventus in the round of 16 of the Champions League.

In the two months since, they haven't inspired confidence that this team, in the state they're in, can pull off what would be an almighty upset against Cristiano Ronaldo and Co.

15. Atletico Madrid

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Atletico aren't necessarily the second-weakest team in the knockouts, but they are one of about seven that don't stand a realistic chance of winning this competition—and of those teams, they drew the shortest straw in the last 16.

They're heading into a bout with European champions Liverpool while low on goals, low on confidence and nursing a few injuries to players who could transform their fortunes if fit (Joao Felix being one).

They're ranked above Lyon because, if some miracle were to occur and both progressed, Atleti would seem slightly better equipped to go on an against-the-odds run.

14. Napoli

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Napoli's turbulent season and up-and-down results make them extremely difficult to gauge; they can look extremely poor one week, and then brilliant the next.

It's notable that their wins tend to come against the better sides—they've beaten Lazio, Juventus and Inter Milan in the last month—suggesting they feel more at home with a reactive game plan in place.

Barcelona are their last-16 opponents, and they'll give them plenty of space to play into on the break. It may make for a tighter game than people are anticipating, but it's still tough to have faith they'll progress.

13. Tottenham Hotspur

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Spurs enter their matchup with RB Leipzig on a three-match win streak—though, to be frank, no one's quite sure how.

There's something to be said for their ability to grind out results, but the frailties shown against Southampton and Aston Villa, plus the sheer amount of luck that led to the win over Manchester City, can't be glossed over just because the games finished as wins.

Play anything like they have in the last three against Leipzig, and they'll be ripped open and punished. It's on Jose Mourinho to produce a tactical masterplan, sans Harry Kane (hamstring), that can best a top side over 180 minutes.

12. Borussia Dortmund

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Man for man, Dortmund are a strong outfit with an incredible attacking corps, but for the last 18 months we've watched them get torn apart defensively by the strongest teams. As a result, it's difficult to put stock in them winning the tournament, considering they drew Paris Saint-Germain in the round of 16.

We've seen them crush Bundesliga minnows and rack up big scorelines, but we've also seen them spring leaks left and right when facing the best.

Dealing with speed in behind is a weak point, making PSG a terrible matchup. January deals for Erling Haaland and Emre Can made them a better team but didn't address an issue that probably dooms them at this level.

11. Atalanta

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The fearlessness that underlined Atalanta's back-from-the-dead qualification for the knockout stages will be on show in the last 16. This team know no other way of playing; they will attack, attack and attack some more.

No doubt they'll find the net against Valencia—in fact, they'll probably manage it multiple times—but it's fair to question two things. First, how they'll deal with Los Che's incisive counter-attacking ability in return, and second, whether they possess the nous to succeed.

10. Chelsea

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Frank Lampard will have been watching on grimly as Bayern Munich's confidence levels and form spiked either side of a nice, refreshing winter break. Meanwhile, his side stuttered a little, completed no January signings and saw the momentum that was carrying their campaign falter.

To get past Bayern they'll have to play perfectly in defence, which they don't seem capable of. They're an exciting, enthusiastic side, but they offer too many chances to opponents, and at this level, that doesn't tend to go unpunished.

If they do produce a 180-minute performance that propels them into the quarter-finals, it'll go down as a key juncture in a young side's development.

9. Valencia

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With no global superstars or fairytale storylines to lean on, Valencia's merits have flown under the radar somewhat.

But anyone who saw them beat Barcelona 2-0 in January can attest to their quality; on their day, they can rip you apart on the counter-attack, using the speed and directness of Rodrigo and Goncalo Guedes to great effect.

As with Atletico Madrid, Valencia don't feel like the ninth-strongest team, but their round-of-16 matchup (Atalanta) plays a part here in a reverse function.

8. RB Leipzig

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We'd call them a dark horse, but because so many are already aware of Leipzig's qualities, would it even be fair to label them as that?

An electric attack led by Timo Werner has tormented almost every defensive corps it has come into contact with this season. They possess the quality and variation to hurt any type of opponent, and they've developed a knack of refusing to be beaten—handy, given the stakes at play.

As with Atalanta, perhaps the question relates to the mental side of the game for Leipzig. This is new ground for every player in the squad; how will they handle it?

7. Bayern Munich

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Ever so steadily, Bayern Munich have crept back to something resembling ominous form under the guidance of stand-in manager Hansi Flick.

They've scored three or more goals in five of their last six games, the other being a goalless draw with fellow round-of-16 German representatives, RB Leipzig. Robert Lewandowski is on fire, the midfield makeup is improved with Joshua Kimmich gluing it together, and Alphonso Davies is a rising star at left-back.

They're favourites for their match against Chelsea for good reason; it feels as though they've got the quality, the confidence and the street smarts to progress.

6. Barcelona

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Every match Quique Setien has taken charge of as Barcelona manager has brought fresh positives but also fresh negatives. Many of the top teams are in flux, but Barca feel the most volatile.

On one hand, they look slicker than before when in possession, and Lionel Messi has turned into a creative machine. On the other, they look extremely vulnerable to counter-attacks, and Messi has lost his shooting boots.

In a comparison to Ernesto Valverde's Barca, they're better to watch but feel more fragile. Time hasn't been on Setien's side, but the business stage of the season starts this week; time is running out.

Napoli's threat on the counter and habit of beating top sides lately will be a big worry for Barca heading into this one. Their overwhelming quality should see them emerge victorious, but if the Italian team is a bad matchup for them, what does that make Paris Saint-Germain or Liverpool?

5. Real Madrid

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Exactly how good are Real Madrid? They're significantly improved compared to this time last year, but this top-tier test against Manchester City will fill in the remaining blanks.

They've reinvented themselves to an extent: Once a free-scoring, overbearing force, they're now a stodgy, obstinate, tiresome team to play against that press and stretch you in ways you won't like.

Los Blancos' hopes of Champions League glory essentially rest on Casemiro continuing in this other-worldly form he's showing, Thibaut Courtois' renaissance lasting the entire season and a few more goals being found from somewhere.

The matchup against City will be tense, tight and fraught, and the winner will announce themselves as a true Champions League contender.

4. Juventus

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Few clubs have placed a higher priority on the Champions League than Juventus have.

Buying Ronaldo was the equivalent of sliding all your chips toward the dealer; they're in win-now mode and are desperate to hoist the trophy, having lost two finals in the past decade.

Still, Ronaldo's clutch qualities can't make the difference on their own, and other players will need to shine if this dream is to become a reality. They haven't been convincing as a team over the last few months but easily have enough to get past Lyon in the round of 16, giving them more time to figure things out.

Like with the Super Bowl, it's often the side who come to the boil at the right time who win this tournament.

3. Manchester City

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If the fact Manchester City are 25 points off Liverpool in the Premier League title "race" hasn't added fire to their Champions League tilt, perhaps news that they're banned from the competition for the next two seasons will.

It'd be best to win the tournament while they still can.

A motivated, determined City side is an extremely dangerous one. With Aymeric Laporte fit again after a knee injury to marshal the defence, they're a serious threat.

2. Paris Saint-Germain

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The commencement of the Champions League knockout stages is the most important part of the season for many, but for PSG, it takes on that extra layer of importance.

Put simply, it defines whether their campaign will be viewed as a success.

This team is phenomenally talented, well-built and balanced, and it possesses the firepower to beat any side in Europe. Between Neymar and Kylian Mbappe, the Parisians boast star quality even Real Madrid cannot.

Their greatest opponent is not necessarily the rival 11 deployed to restrain them, but the ghosts of their past failures, such as La Remontada, or Manchester United last year.

The talent has always been there—the composure and execution always absent. But 2019-20 feels different.

1. Liverpool

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No surprises here: Liverpool, the European champions, the team in the middle of an unbeaten Premier League season, the side who have taken 103 points from the last 105 available, are ranked No. 1. There's no need to overthink it.

Even at their worst, at their most vulnerable, they seem to grind out wins—and when they do click, they blow you away. The various injury issues that have bugged their season seem to have cleared up, meaning they're virtually at full strength in time for the knockouts.

Their round-of-16 draw was favourable, with Atletico Madrid poorly equipped to do what's necessary to beat the Reds. No game at this stage is a foregone conclusion, but...

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