Mohamed Salah needs to produce his record-breaking season year after year to earn comparisons to Cristiano Ronaldo, says Liverpool goalkeeper Loris Karius.
Salah's spectacular first campaign for the Reds after joining from Roma saw him set a new record for the most goals scored in a 38-game Premier League campaign.
The Egypt international also claimed a raft of individual prizes along with the Premier League Golden Boot, including Professional Footballers' Association and Football Writers' Association Player of the Year prizes.
Dejan Lovren has claimed Salah is "definitely" the best player in the world on current form as Liverpool prepare to face Madrid in Saturday's Champions League final in Kiev.
But, with the clash being billed by many as a battle between Salah and five-time Ballon d'Or winner Ronaldo, Karius believes the Portugal star remains on another level.
"This season is unbelievable," Karius told Sky Germany. "He's of course in that region but the biggest difference is Ronaldo did this over so many years.
"It's too early to put Mo with him. I don't want to take anything away from Mo - he's world-class this season.
"But Ronaldo showed himself over so many years to be up there with the best, you have to prove it season over season.
"I hope he can do it. I wish he can do it. He's still really young and has a lot of space to improve even more."