The two attackers will face off on Wednesday night in the first-leg of the Champions League semifinal.
"He's a great, great player," Mane said about Coutinho.
"I was a bit jealous that Barcelona got him!
"He's still young and will improve a lot because he's a hard worker."
Finally, he revealed the secret behind his fruitful season.
"To be honest, the secret behind my performance is the team," Mane noted.
"We help each other and give everything we have as a team to get a positive result on the pitch.
"Supporting each other is very important."