Rio Ferdinand has joked that Mohamed Salah needs another "15 seasons" like his Liverpool debut campaign to be compared to Cristiano Ronaldo.

Salah netted his 39th goal of the season as the Reds beat Manchester City 2-1 at the Etihad Stadium on Tuesday night to seal their spot in the Champions League semi-finals.

Real Madrid forward Ronaldo, meanwhile, has scored 23 times in his last 13 matches in all competitions, and has 40 goals from 37 games this campaign.

"He's doing alright," former Manchester United defender Ferdinand said about Salah on BT Sport.

"To put it into perspective, Salah is talked about rightly as having an unbelievable season. But he's going to have to do that for the next 15 seasons to get to [Ronaldo's] mark."

Salah is contracted to Liverpool until June 2022, while Ronaldo is tied to Los Blancos until June 2021.