The Egypt international has far exceeded all expectations since his arrival at Liverpool, but which other players made similarly massive impacts?
Getty ImagesGareth Bale (Real Madrid)
Arriving at Santiago Bernabeu as the most expensive player in history, much was expected of Bale, and he did not disappoint in his debut campaign.
Directly involved in 28 goals in just 27 Liga matches, the Wales international also scored in the finals of both the Copa del Rey and Champions League as Carlo Ancelotti's side won both competitions.
AdvertisementGetty ImagesWesley Sneijder & Diego Milito (Inter)
Signed by Jose Mourinho ahead of the 2009-10 campaign, Sneijder and Milito combined to help Inter secure one of the most famous trebles in European history.
Sneijder's performances saw him win the Goal 50 – though he did controversially miss out on a Ballon d'Or nomination – while Milito scored 30 goals in all competitions, including the winner in the Coppa Italia final and both goals to beat Bayern Munich in the final of the Champions League.
Getty ImagesN'Golo Kante (Leicester City & Chelsea)
An unknown when he arrived at the King Power Stadium, Kante was a force to be reckoned with in midfield as his ability to tackle and intercept almost at will formed the base around which Leicester's title win was built.
He unsurprisingly earned a big money move off the back of that, only to take his performance level up a notch at Chelsea where he picked up a second consecutive Premier League winner's medal as well as both the PFA and Football Writer's Player of the Year awards.
Getty ImagesRonaldo (Barcelona)
Signed for a world record fee, Ronaldo proved to be a force of nature during his sole campaign at Camp Nou, scoring 47 goals in 49 matches across all competitions.
His goalscoring exploits saw him become the youngest winner of the FIFA World Player of the Year award at the age of just 20.