UEFA Champions League | Liverpool 0 – Porto 0

The Reds' lacklustre performance hardly mattered, though, after a devastating 5-0 win in Portugal three weeks ago all-but secured a first appearance in the last-eight since 2008-09.

That first-leg cushion enabled Jurgen Klopp to make five changes to the side that beat Newcastle United 2-0 on Saturday, with leading goalscorer Mohamed Salah dropping to the bench for Adam Lallana, who was making his first start in two months. 

Sadio Mane had two clear chances to open the scoring in the first half, the second of which crashed against the post, while Dejan Lovren headed over.

James Milner and Roberto Firmino also squandered opportunities in the second period and Lovren blocked a late effort from Oliver Torres to ensure the Reds remain one of three unbeaten sides in this year's competition alongside Tottenham and Barcelona.

Liverpool were a long way from their swashbuckling Premier League form and Klopp will hope they have not lost any impetus ahead of the crunch clash against Manchester United at Old Trafford on Saturday.