Telles shone on debut in victory at Champions League opponents PSG, while Van de Beek is already amongst the goals.
Giggs believes Telles can give United something they haven't had, and that last season's champions Liverpool have in abundance.
The Wales manager said: “I think for van de Beek, it's how he gets into the team, but when he has come on, he's impressed. He looks like he's always got a goal in him.
“Telles, I think that's something we've been missing. You look at Liverpool, Trent and Robertson - the goals that they provide. Now, full-backs have to have that in their armour. If the wingers are coming in, the full-backs have to create the width and make goals."