Unai Emery turned down the chance to sign Liverpool forward Mohamed Salah while at Paris Saint-Germain due to having concerns over the Egypt international.
The decision came while Salah was plying his trade at Roma, where he spent 12 months on loan and a further year on a permanent deal.
Salah went on to join Liverpool for a then club-record £36 million (€46m), which could rise by £7m due to a series of add-ons, and netted 44 times in his maiden campaign at Anfield.
That form has continued into the 2018-19 campaign, with the 26-year-old having found the net 15 times for the Reds, who lead the Premier League table at the halfway stage.
Emery will come face-to-face with the player he rejected when Liverpool host Arsenal on Saturday evening.
But the Spaniard no longer has doubts regarding Salah, who is now a player he rates as one of the best in the game.
“We spoke about the possibility of signing Salah to Paris Saint-Germain when he was playing at Roma,” Emery said.
“We had some concerns and then he signed for Liverpool [in June 2017]. These concerns have gone.
“Now if you are speaking about the five top players in the world, one is Salah.
“Today I can say to you, if we were to sign him, we would be signing a player in the top five in the world.”