The 24-year-old joined Liverpool for £30 million today.
The Senegalese flyer proved himself a handy goalscorer during his stint with Southampton, netting 24 times in all competitions after being signed by Ronald Koeman - now at Everton - two years ago.
Liverpool fans for the most part will be happy with the acquisition, but one man who isn't is Nicol, who claims that not only is Mane inconsistent, but warns that his personality may incur the wrath of Klopp.
"I'm not over the moon. This is a guy who can be dynamic, who can score goals, but by all accounts can be a pain in the backside for the coach as well," he told ESPN.
"Mane falls into the trap with a lot of Liverpool players right now: they can be great, or they can poor, and I'm not exactly carried away with it."
Nicol, who spent 13 years at Liverpool, is clearly unimpressed, but the 54-year-old's former team-mate with the Reds Don Hutchison has sent the club's new signing his best wishes on Twitter
Sadio Mane— Don Hutchison (@donhutch4) June 28, 2016
All the very best at one of the best footballing cities!! ❤️
There is perhaps a touch of truth in regards to what Nicol says about Mane being inconsistent, but Klopp is one of the best man-managers around and the German might feel confident that he can help him shine on a regular basis next season.