Mohamed Salah played like Lionel Messi in training at Chelsea and Jose Mourinho failed to get the best out of the star forward, according to former Blues team-mate Filipe Luis.
Chelsea bought Salah to the Premier League in January 2014 after striking a reported £11million fee with Swiss side Basel.
But it was an unhappy spell for the Egypt international under Mourinho, with Salah starting just 10 games, scoring twice and supplying three assists before being shipped off on loan to Fiorentina a year later.
A spell at Roma followed his time with the Viola and it was his impressive performances in Serie A that convinced Liverpool to give him a second chance in English football.
With the Reds, Salah has become a Premier League and Champions League winner, and Filipe Luis – who similar difficulties forcing his way into Mourinho's plans – said his talent was always evident at Stamford Bridge.
"I won the league with him [Mourinho]. But he didn't get the best out of me, just as he didn't with Salah," the former Brazil international told the Guardian.
"When he went Fiorentina, I said: 'Why are you going, Momo? This is Chelsea.' And he said: 'I need to play.' I thought: 'This kid's good.' He never went for money or to win more; he went to show he could play. In training he was like Messi. Really, like Messi. Ask anyone."
Filipe Luis arrived at Chelsea in July 2014 having just won LaLiga with Atletico Madrid, a club with whom he was also a Copa del Rey and Europa League winner and a Champions League runner-up prior to moving to London.
Despite his reputation as one of the best left-backs in the world at that time, Mourinho afforded him just 26 appearances in all competitions and nine starts in the Premier League.
However, reflecting on that time in his career Filipe Luis insists he harbours no ill will towards Mourinho and accepts the form of Cesar Azpilicueta meant he could have few complaints.
"I haven't told anyone this but the first game I knocked on [Jose] Mourinho's door," he said. "'Can I talk to you?' 'Come in.' 'Why did you bring me here? You took me from a place I was happy, where I played every week. You signed me to play. And the first day against Burnley I'm on the bench. Why not leave me at Atletico? Why bring me here not to play?'
"He said he didn't think I was playing well and Azpilicueta was, that he didn't feel as secure with me. I had to win my place; I couldn't expect to be first choice on reputation. And looking back, he was right.
"He played so well he never gave me a chance. Mourinho rotated so I did get chances but I didn't start big games because the team was playing perfectly. We had great players. Eden Hazard, [Cesc] Fabregas, Diego Costa."
Hazard, a modern-day Blues great, was a player who Filipe Luis was particularly enthralled by.
"Alongside Neymar, Eden's the best I've played with. He's up there with Messi, winning games alone.
"He didn't run to defend much, didn't train well, and five minutes before games he'd be playing Mario Kart in the dressing room. He trained and warmed up laces untied. But he'd go out and no one could take the ball. He'd dribble three or four. If opponents got too close, he'd just pull away, so powerful.
"So intelligent: one-two, combine, go alone; assist, score, everything. Maybe he lacks the ambition to say 'I'll be the world's best', because he could be. For talent, the best.
"Cesc had an extraordinary season too. And Costa. Then the defence was incredible. John Terry's one of the best captains I've had. Even the bench: Oscar, Obi Mikel, Mohamed Salah, [Andre] Schurrle, Kurt Zouma, [Didier] Drogba, Loic Remy. Some team."