Champions League holders Bayern Munich return to European action on Tuesday for the start of the knock-out stage.

Liverpool, Paris St Germain and Borussia Dortmund gained victories on the road last week and several other heavyweights will resume their campaign with round of 16 ties in the coming days.

Here, the PA news agency takes a look at the key talking points before the four matches to be played on Tuesday and Wednesday.

Can Bayern go back-to-back

Two of the best goalscorers in Europe will face off at the Stadio Olimpico. While Robert Lewandowski finished with the most goals in the 2019-20 Champions League, he was pipped overall by Ciro Immobile. The Italian found the net on 36 occasions for Lazio in Serie A, the most of any player in Europe’s top five leagues. Bayern ace Lewandowski was only two off that tally but will be out to show who is top dog during Tuesday’s round of 16 first leg. Lazio’s number 17 has not rested on his laurels though and has 19 goals already this term.

Suarez faces his old foes again

There is no love lost between Luis Suarez and the Chelsea fans. It was back in 2013 the Uruguayan received a 10-match ban for a bite on Branislav Ivanovic at Anfield. It has not been forgotten by the Blues faithful but the former Liverpool striker does not boast the best of records against the Premier League side. He has scored only twice in nine appearances but with eight already to his name in 2021 with Atletico Madrid, the 34-year-old will be out to improve that during this two-legged tie.

Is this City’s year?

Real Madrid are the most successful team in the competition with 22 wins and claimed three in a row between 2016 and 2018. However since that success over Liverpool three years ago, Los Blancos have failed to make it past the round of 16. Ajax and Man City have proved too strong at this stage during the past two campaigns and in Atalanta this time, Zinedine Zidane will know they are facing an up and coming outfit. The Italians won at Anfield in November and were within touching distance of the quarter-finals last year.