The Senegalese star warned his Anfield team-mate of the talent his fellow countryman possesses after his switch to Vicarage Road this summer
Liverpool attacker Sadio Mane has revealed he told Andrew Robertson that Watford's summer signing Ismaila Sarr would "kill him" with his pace and dribbling ability.
The 22-year-old became the Hornets' club-record signing when he arrived at Vicarage Road from Rennes for £30 million ($37m) on deadline day.
Sarr is a product of Senegal's famed Generation Foot academy, which is also responsible for Mane's rise through the ranks as a youth player.