Arsenal boss Unai Emery decided against signing Mohamed Salah for Paris Saint-Germain due to doubts over the Liverpool star's readiness for a big club.
Emery described Salah as having developed into one of the top five players in the world, but was less sure of his ability to adapt to more intense expectations during his two-season spell at Roma.
The Gunners will get a close-up view of the forward's talents when they meet Jurgen Klopp's table-toppers at Anfield on Saturday.
Salah, 26, enters the match with five goals in his past four Premier League appearances, having continued the free-scoring form that saw him notch 32 times in the top flight last term.
That incredible campaign may have come as something of a surprise to Emery.
"We spoke about the possibility to sign Salah to PSG when he was playing at Roma," the Spaniard said.
"We had some doubts, and then he signed for Liverpool and these doubts he has broken."
Asked about the nature of the concerns, Emery added: "How he can take the performance into one big team. Like PSG, for example."
However, the ex-Sevilla head coach now needs no convincing as to where the reigning Premier League Golden Boot winner ranks among the best in the game.
"Now if you are speaking about the five top players in the world, one is Salah," he said.
"Today I can say to you, if we sign him, we sign one player in the top five in the world."
Arsenal are 13 points adrift of Liverpool, who are unbeaten in all 19 of their league fixtures and six points clear at the top.