The Senegalese forward already had scored one goal on Wednesday night after Jose Sa let his shot slip under his body in the 24th minute. However, Mane wasted little time adding to his tally in the second half.
After team-mate Mohamed Salah slotted home a rebound for Liverpool's second, the 25-year-old followed suit, getting on the end of a shot from Roberto Firmino which the Porto goalkeeper had parried right into his path.
Mane had no trouble sending it into the back of the net to give the 'Reds' a 3-0 lead away from home.
Check the goal out for yourself:
14 February 2018