The United ace continues to set records that are unlikely to be broken as he gets set for his fourth European Cup Final at the age of 37.
And Speed is convinced that Giggs is still the main man when it comes to the biggest stage of all. Speed, who played alongside Giggs for Wales, said: "Ryan is still one of the very best, if not the best - and he's 37.
"He's adapted to this role of central midfield now and shown people just how comfortable he is in there.
"To be honest, he's made that role his own but he could have played there when he was a teenager, he was that good.
"Messi is definitely right up there, in my opinion. For the past two or three years he's been absolutely phenomenal.
"He seems like a decent lad, too. He could be at Barcelona for the next decade and if he does, he'll be one of the all-time greats - up there with the likes of Pele and Maradona.
"But what Ryan has done is unbelievable. His record is better than anyone who has ever played the game.
"It doesn't surprise me though. I know better than most how he looks after himself and what he does to be a success.
"I did a lot of yoga when I was playing at Newcastle and Bolton, and I chatted to Ryan about it all.
"But I think he started all that before I did. It's something that helped me to carry on and it's certainly helped Ryan continue to the age he has.
"Along with Bobby Charlton and Kenny Dalglish, I'd say he's up there as the best British player of all time and certainly the best the Premier League has seen.
"You can only judge greatness on achievement and while I'm sure Messi will go on to win a lot more in his career, Ryan has won the lot several times over.
"He's achieved a lot more and is still going, so he's up there as one of the best ever."