The move was confirmed less than two hours after the player touched down in Valencia, where he completed the final paperwork needed before the signing was made official. Speaking at Manises Airport, Dieng expressed his delight at starting this new chapter of his career.
"I am very happy to be here," he told reporters present at the airport. The Mali international revealed he had already spoken with Valencia head coach Carlos Corberan.
"Of course I've spoken with Corberan. I know he expects a lot from me and I hope to give my best version to the team," he said.
Dieng also stressed what the move to LaLiga means for his career.
"This is a big step in my career, to be able to be at Valencia and in LaLiga," he said. Asked about the club's ambitions for the coming season, he was clear. "The goal is to experience Champions League nights again, to return to Europe."
Dieng, born in Bamako, Mali, on October 16 1997, arrives from Al Ahly, one of the most decorated clubs in African football. Since joining the Egyptian side in 2019, he made 250 official appearances and built up an impressive collection of honours, including three league titles, two domestic cups and four Egyptian Super Cups, as well as four CAF Champions Leagues and two CAF Super Cups.
At international level, the midfielder is one of the leading figures for the Mali national team, whom he captains and is a regular starter for in major fixtures, including the recent Africa Cup of Nations.
With his arrival, Valencia strengthen a position that had been among the priorities of their squad planning, even after the winter market saw them bring in Guido Rodriguez for the same role. The club describe Dieng as a "central midfielder with physical presence, ground coverage and defensive solidity, as well as the ability to give continuity to play from the first pass."
He becomes the fourth confirmed arrival of Valencia's summer rebuild, following the signings of Justin de Haas, Ryunosuke Sato and Guido Rodriguez as Corberan continues reshaping his squad.
Dieng will be officially presented on Wednesday, after which he will join up with the coaching staff and begin integrating into pre-season training as Valencia continue their preparations for the new campaign.