Cape Town - Liverpool were in imperious form as they demolished Watford 6-1 in their Premier League clash at Anfield on Sunday afternoon.
The Reds dominated the first half with Mane wasting an early chance as Can skipped down the left flank before feeding his teammate with a good cross.
Firmino then headed into the arms of Heurelho Gomes from an Adam Lallana delivery before Loris Karius comfortably saved from lively right-winger Nordin Amrabat.
Lucas, who hasn't scored for Liverpool for six seasons, flashed a header wide of the Watford goal before Jose Holebas did well to force Lallana wide as he looked to latch on a great throughball from Firmino.
Lucan then fired straight at Gomes from close range after a Firmino flick from Coutinho's corner, on 17 minutes.
Coutinho was offside as he hit a post moments later before firing agonisingly wide after picking up a good Mane ball.
Gomes then got down well to deny James Milner before Firmino skewed his shot just wide of the target.
But the goal Liverpool were threatening soon arrived as Mane flicked his header into the far post from a short corner from Lallana, on 27 minutes.
Coutinho then made up for his raft of misses with a good finish inside the near post from a central area after being fed in on goal by Firmino.
Gomes picked up an injury and was replaced by Costel Pantilimon before Can made it three with a finish at the back post from a Lallana cross from the right after Firmino had headed a Karius free-kick into Coutinho's path who found his teammate out wide.
Coutinho fired over the crossbar five minutes into the second half before Karius did well to hold onto a Janmaat shot.
Henderson hit a speculative effort just over before Firmino was able to tap home a fourth for the hosts after a Lallana ball into the box from a Henderson touch following Coutinho's free-kick.
And the game was well and truly beyond Watford when Mane added a fifth on the hour mark, with another tap-in, from a Milner ball from the left.
Karius denied Etienne Capoue with a super diving save on 68 minutes before the Reds stopper got enough on the ball to stop it trickling over the line after some good approach play from Troy Deeney.
It was a better spell from Watford though and they were rewarded with a fine goal from Janmaart, who curled a low shot into the far post after picking up a cross from Amrabat.
It was all Watford as Karius was forced to get down to keep out an Odion Ighalo strike from the right hand side before Liverpool substitute Daniel Sturridge, on for Lallana smashed his 80th minute shot against a post.
Pantilimon then made a good stop to deny Sturridge in the closing stages as Coutinho fired well over the target with Liverpool looking to end strongly.
Sturridge was looking sharp as he smashed a shot onto the Watford crossbar via a slight touch from Pantilimon before the giant stopper made a point-blank save from Firmino.
Sturridge looked a man possesses and forced Pantilimon into two good saves, although substitute Georginio Wijnaldum had the final say as he was on hand to fire home the rebound from Sturridge's second effort.