The 22-year-old has impressed in training recently since signing in the summer from Ole Gunnar Solskjaer’s former club Molde, for whom he has since been playing on loan.
Diouf has made one appearance for the senior Senegal national side, and is at United's disposal next month because his country didn't qualify for the 2010 Africa Cup of Nations.
The powerful, quick and direct frontman boats an excellent strike-rate at Molde – his record this season is 16 goals in 29 matches.
If Sir Alex’s glowing appraisal is anything to go by, Diouf may get a chance in the first team sooner rather than later, although he won’t be available for the FA Cup tie against Leeds on 3 January.
Sir Alex said earlier this month: “If you’re talking about value then you can look at our young boy Diouf.
"He’s been training with us and is looking very exciting. That’s the kind of situation we’re good at – finding young players who can develop at the club and at 22 years of age he’s looking very good.”