Mane's fellow Senegalese scored twice as the disjointed Reds crashed to their first Premier League defeat of the season at Vicarage Road on Saturday evening.
Sadio Mane warned his Liverpool teammates about Ismaila Sarr's quality back in August, six months before his fellow Senegalese ended the Reds' unbeaten Premier League season.
Watford's Sarr scored twice at Vicarage Road on Saturday as Watford ensured Liverpool slipped to a defeat for the first time this season, and a first time in 45 league matches.
Troy Deeney added a third as the the relegation-threatened Hornets earned a dominant 3-0 win, but it was Sarr who really caught the eye as he bagged a brace.
The 22-year-old joined Watford for a club record fee of £30million from Rennes in the summer, and Mane tipped him to be a future Premier League star.
“The first day he signed I sent him a message to say good luck and that I was happy for him,” Mane told The Athletic in August shortly after Sarr joined Watford .
(Image: REUTERS)
“He’s rapid. I think defenders will struggle. Last time I was speaking to Robbo (Andy Robertson) I said ‘ Watford have a really good player. I will need to help you more otherwise Ismaila Sarr will kill you, because he is a good dribbler and very, very fast'."
Mane was filed chatting to Sarr in the Anfield tunnel after Liverpool's 2-0 win over Watford in December, and he has also spoken of himself as something of a father figure for the winger.
“I’m really happy for him and he made the right choice to come to Watford. For sure I think he will be great," he continued.
As Jurgen Klopp tried to deliver his assessment of Liverpool's shock Premier League defeat at Watford, he found himself having to speak louder than he probably would have liked.
Despite the microphones and speakers set up in the press conference room within the bowels of Vicarage Road, the noise of celebrating Watford fans just outside was virtually drowning him out.
The narrative that preceded Saturday's 3-0 win for the Hornets was all about Liverpool. A hundred or so members of the press had packed into the old stadium with just one angle on their mind - Liverpool were on the verge of making English top-flight history, with another win on their relentless march towards the Premier League title meaning a record-breaking 19th in a row.
Pre-match talk was not only about Liverpool setting such a record but also whether they could match the Arsenal "Invicibles" achievement of going an entire season unbeaten.
Few would have expected both of those records to be torn apart by a Watford side that started the day in the relegation zone and had not won in their five previous outings.
Liverpool's 3-0 loss was the biggest margin of defeat for a side starting the day top of the Premier League since November 2015
But that is exactly what happened.
How? Put simply, Watford were the better side from start to finish. They pressed Liverpool high up the pitch and were quick to close down the Reds whenever they ventured towards the Hornets box.
Klopp himself - well aware that the headlines would be about Liverpool's defeat - was keen to direct praise towards Watford.
"3-0 is a bit harsh but we had a big hand in that," he said.
"The most important thing is congratulations Watford - well deserved. That should be the headline. We didn't perform like we should have and Watford performed exactly how they want."
There were, of course, negatives within Liverpool's performance that contributed to the defeat.
Dejan Lovren made his first Premier League start since 7 December as Joe Gomez missed out because of a minor fitness concern and the Croatia international looked rusty as he struggled to deal with the pace and trickery of Ismaila Sarr, who twice got the better of the Reds to score.
Lovren started the last time Liverpool lost by three goals - the 2017 4-1 defeat by Tottenham - but he was not alone in having an off day. His defensive partner Virgil van Dijk made a number of uncharacteristic mistakes, while Fabinho was also considerably off the boil in midfield.
"In the first half there were little football things that didn't work out for us," added Klopp.
"Things we usually do naturally right we didn't do right. That already made the game pretty tense. We spoke about football things at half time and I really liked the start of the second half. The reaction was good but then we conceded the first goal and not long after that we conceded the second.
"But it has nothing to do with the games we won before and the games we will win - it was just this one football game and we have to admit we lost to the better team."
The home crowd, too, played a part.
Before kick-off the atmosphere around the ground was not one of despondency but one of belief that Watford were doing the right things, despite recent results saying otherwise.
They encouraged their team from the outset, rather than groaning at anything that did not come off, and when Sarr broke the lines with one of many promising runs on the flank early in the first half, they roared with an encouragement that clearly rubbed off on the players.
But much like Klopp, Watford boss Nigel Pearson did not want to overplay the significance of the result in their battle for Premier League survival.
"It is just one game," he said of the win that moved his side out of the bottom three on goal difference.
"We have 10 left and we have to try and emulate today in terms of performance.
"The results have not been what we wanted. We found it difficult to find ways of winning games. We coped exceptionally well today and that is the most important for me."
Watford secured their first top-flight victory against a side starting the day top of the table since the final day of the 1982-83 season, also beating Liverpool that day (2-1)
So what does this mean for Liverpool?
They are 22 points clear at the top of the table so, ultimately, it is the slightest of bumps in the road as they close in on a first league title in 30 years.
Instead the Reds will, as the phrase so attached to them goes, simply "go again" but now unburdened by the pressure of chasing records.
"I see it [the defeat] as rather positive," Klopp said. "From now on we can play free football again, we don't have to defend to try to get records.
Everton are keen on agreeing a new deal with Mason Holgate.
The 23-year-old has done well under Carlo Ancelotti and the Toffees want to reward him for his progress according to The Times.
The young defender’s current deal expires in 2022 and he has been at the club since 2015.
Holgate is highly rated at the club and he is expected to lead Everton’s defence for years to come. The decision to offer him a new deal is hardly surprising.
He has been one of Everton’s most improved players since the arrival of the Italian manager.
The player and the fans will be delighted with the news. It will be interesting to see if Everton manage to wrap up the agreement soon.
Holgate will want to continue his development as a footballer under a world-class manager like Ancelotti and therefore he should agree to the renewal.
Everton need talented young defenders like Holgate and Ancelotti should look to bring in a quality partner for him in the summer.
The likes of Mina and Keane have been quite inconsistent and unreliable this season.
Some of the Everton fans are quite happy with the news and they have taken to Twitter to share their thoughts on a potential new deal for Holgate.
