Karlsen, who has worked for Watford, Bayer Leverkusen and Hannover, said in a column for skysports.com: "Diouf was already a hot topic among European scouts when Molde hosted Brann last Sunday. In front of a dozen potential buyers the hot shot striker scored four goals, including a hat-trick within the opening ten minutes of the game.
"The astonishing display of power, strength and finesse stoked the rumours linking the striker with a move abroad to a roar, with several German, Dutch and French clubs reportedly interested in signing the player. Yet when Old Trafford was revealed as the player's destination at a press conference given by Molde on Friday lunchtime, there was a general feeling of disbelief that he should end up at such a club."
He also said: "So will the gamble pay off? Diouf's ability to perform in a physical European league speaks in his favour and he's hoping to follow in the footsteps of John Obi Mikel, another African recruit via Norwegian league football which, bar the obvious shortcomings in technique and overall quality, is comparable to the Premier League in that the pace is high and time on the ball is limited.
"And whereas dozens of African players have failed to settle in Scandinavia, Diouf has adapted to the harsh, chilly climate of coastal Norway (coming from tropical Senegal he was already accustomed to heavy rainfall - so Manchester should be a doddle for him) and developed into a hard-working, disciplined and tactically adept team player who has also blended in well socially, showing a maturity that beggars his young age. "