Beckham says United have to watch out for Inter Milan’s forward duo Adriano and Zlatan Ibrahimovic.
The former Manchester United star played against Inter for rivals AC Milan in the derby last Sunday.
Beckham said: “Inter have got top players throughout their team but the two forwards are the players who can cause the most problems.
“But United have got great defenders and don’t forget, Inter will also be worried about the players United have got in attack.”
United are still in the race to win an impressive Quadruple this season.
Beckham added: “I really hope they’ll win every one of them.
“It would be amazing if they could.
“It was a fantastic achievement when we won the Treble in ’99 and for them to be involved in four competitions this season is brilliant.
“Their squad is so strong all the way through from the goalkeeper to the strikers.
“It’s an amazing squad of players and I’m sure they’ll go on to achieve great things.”