Liverpool resume their Champions League quest with a quarter-final first leg against FC Porto at Anfield on Tuesday night.

Just over a year after the Reds eliminated Sergio Conceicao’s side at the Round of 16 stage, they meet again for the right to face either FC Barcelona or Manchester United in the last four.

Here are three key battles that could decide the outcome tomorrow evening…

Jordan Henderson v Danilo

Jordan Henderson’s performance off the bench in Friday night’s 3-1 win over Southampton is likely to make the question not if the captain plays against Porto but where.

Typically deployed as the deepest of a central three under Jürgen Klopp, the No.14 was sent on in a more attack-minded role at St Mary’s and rose to the task with an assist and a goal to help the Reds reclaim top spot in the Premier League.

Wherever he is used on Tuesday night, Henderson will aim to reproduce his dominant display in the home leg of Liverpool’s previous knockout tie, against Bayern Munich.

That evening, the England international topped his team’s tallies for passes (72), passes in the opposition half (41), tackles (four) and possession regains (eight).

Henderson can expect to be in direct confrontation with Porto’s Portuguese midfielder Danilo Pereira, who has played every minute of their Champions League campaign so far.

The 27-year-old boasts the highest passing completion of his side’s regular participants in the tournament this term (89 per cent) and only teammate Hector Herrera can better his 85.8km covered in eight matches.

And Danilo’s responsibility will be heightened at Anfield due to Herrera’s suspension for the game – the first time in this season’s competition that the pair will not line up together.

Virgil van Dijk v Moussa Marega

While strike partner Tiquinho Soares beats his tally of 17 in all competitions this season, Moussa Marega has been Porto’s chief Champions League goal-getter.

The Malian forward has netted six times in seven appearances in the tournament, including one that sent the Round of 16 tie with AS Roma to extra-time after assisting Tiquinho’s effort earlier in the second leg.

Marega has experienced something of a dry spell in 2019, however, with the goal against Roma last month only his second of the calendar year for the club.

Should he continue to line up on the right of a two-man Porto frontline, Marega can anticipate a tough battle with Liverpool’s dominant Virgil van Dijk, who is stationed as the left-sided central defender.

The Netherlands international has been a model of consistency since signing for the Reds from Southampton in January 2018 and of course helped Klopp’s men reach last year’s final.

Van Dijk also showed his potential influence going in the other direction when he returned from suspension for the decisive second leg with Bayern at the Allianz Arena four weeks ago.

His raking pass set up Sadio Mane to secure a breakthrough away goal and it was his powerful header that restored Liverpool’s advantage and turned the tie fully in their favour.

Roberto Firmino v Felipe

Roberto Firmino is finding form at just the right time as Liverpool pursue glory in both the Premier League and the Champions League.

The Brazilian has claimed three goals and two assists in his last five games for the Reds, the latest a trademark example of selfless running and creativity to tee up Henderson’s late strike at Southampton.

And the No.9 – who has scored seven times in his past seven outings at Anfield – will be eager to grow his total of two strikes in the competition this season at the expense of Porto.

To do so, Firmino must get the better of another of Os Dragoes’ ever-presents, his compatriot Felipe.

With the experienced Pepe suspended for the trip to Merseyside, much responsibility will lay on the 29-year-old’s shoulders if Porto – who have registered only one Champions League clean sheet this season and none away from home – are to thwart the Reds.

The 6ft 3in defender, now in his third season with the Portuguese outfit, does not have to look too far for inspiration, though; he helped shut out Firmino and Liverpool at Anfield in the teams’ last-16 second leg in 2018, having missed the 5-0 defeat in the first match.