The Champions League returns with a bang this week as Europe's biggest competition reaches the last 16.

Defending champions Manchester City are up against FC Copenhagen, with European heavyweights Real Madrid, Paris Saint-Germain and Bayern Munich also in action in the first of two weeks of games.

Here are some of the key talking points ahead of a thrilling few days of action.

The double Treble?

Few teams in the history of football have achieved what Treble winners City did last season and repeating the trick once again would surely be an unprecedented feat.

After a few early hiccups, Pep Guardiola's men look to be clicking into gear after winning their last 10 games in all competitions.

They remain favourites for the Premier League title, will fancy their chances in the FA Cup and while another deep European adventure will be hard to pull off, they look as well equipped as any team.

A convincing performance against Copenhagen in Denmark on Tuesday would show the rest of Europe's contenders that they mean business once again.

England duo's European dream

Though there were two English casualties in the group stages, two of the Three Lions' best talents are bidding for glory with clubs from abroad.

Jude Bellingham and Harry Kane are two of Europe's biggest stars right now, starring for clubs with a wealth of European pedigree.

Young sensation Bellingham, 20, has quickly become a talisman for 14-time winners Real, scoring 20 goals and eight assists during his first season — unfortunately he will miss Tuesday's away clash against RB Leipzig with a sprained ankle.

Kane has been a similar hit with Bayern, who travel to Lazio on Wednesday evening.

Struggles in the Bundesliga are likely to make the England captain even more determined to claim a first Champions League title with the six-time European champions.

Dark horses

PSG are still in search of an elusive first triumph in the competition and are up against a difficult opponent.

Many are naming Real Sociedad as the dark horses to go deep this season after going unbeaten and finishing top of their group — as Kylian Mbappe and Co squeezed through theirs.

The likes of Mikel Oyarzabal, Takefusa Kubo and Martin Zubimendi will be threats for PSG to deal with in the French capital on Wednesday, while they also have Arsenal loanee Kieran Tierney at left-back.

Luis Enrique's men are top of Ligue 1 but have not looked all that convincing this season and this tie seems the most likely one to deliver a shock.

Golden Boot battle

Erling Haaland has returned to full fitness just in time to boost his hopes of collecting another Champions League Golden Boot.

The Norwegian has five goals this term — the same as Atletico Madrid duo Alvaro Morata and Antoine Griezmann as well as Rasmus Hojlund, who will not be able to add to his tally after Manchester United's group-stage exit.

City team-mate Julian Alvarez is also in the running on four goals — with Kane, Bellingham and Arsenal striker Gabriel Jesus among the others to net the same in the group stage.

Haaland has plenty of competition for the prize but has a chance to pull away from the rest of the group during tomorrow's trip to Denmark.