While Aaron Wan-Bissaka was a big-money addition last year, and Brandon Williams began to make the breakthrough, neither they nor Luke Shaw regularly offered a goal or creativity threat in the final third.
Wales manager Giggs says Telles, who turns 28 in December, can bring that to the team in the way rivals Liverpool rely on Trent Alexander-Arnold and Andy Robertson on either side of the pitch.
"Telles, I think that’s something we’ve been missing," Giggs said on the Webby and O’Neill YouTube channel.
"You look at Liverpool, Trent and Robertson - the goals and assists 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.”
Fellow former United midfielder Owen Hargreaves added that playing the wide role in a back three system would likely suit the new arrival well, as he was not the most reliable option in his own half and would thus have extra protection behind him.
“He is a good player, a great attacking player,” he said on BT Sports.
"He gets assists, works up and down - he's probably more suited to playing as a wing-back because defensively he's not great.
“In terms of assists, his numbers are off the charts. He's great on set pieces, he's a good addition to United, a modern full-back.”