He revealed that under Sir Alex Ferguson, the Red Devils had a similar situation against Juventus.
United were beaten by them in 1996 and 1997 when they had the likes of Zinedine Zidane and Alessandro Del Piero in their ranks.
In 1999, they overcome the Italians on a famous night in Turin on their way to the treble.
Giggs also scored twice for United in a 3-0 victory away from home in 2003.
Now manager of Wales, the 44-year-old said: “United were second best the other week.
Man Utd news: Giggs scored a brace against Juventus in 2003 (Image: GETTY)
“Juventus were fantastic and United didn't turn up.
“But United have the players, I think it will be closer on Wednesday.
"It is about realising you have to get to that level.
“How do you do that? You have to perform week in, week out, training every day and realising what it takes to be the best club in Europe and be part of that as an individual.
We use your sign-up to provide content in ways you've consented to and to improve our understanding of you. This may include adverts from us and 3rd parties based on our understanding. You can unsubscribe at any time. Read our Privacy Policy
Man Utd news: Giggs was part of the United side to beat Juve in 1999 on their way to the treble (Image: GETTY)
Man Utd news: Jose Mourinho's side will have to be at their best in Turin (Image: GETTY)
"We faced the likes of Zidane, Boksic, Davids, Del Piero but we had players who were capable of doing it too and they did.”
United have recorded back to back victories in the Premier League against Everton and Bournemouth and will need to be at the top of their game against Cristiano Ronaldo and co.
“I've been really impressed with United in the last four or five games, especially second half,” Giggs added.
“Bournemouth on Saturday were brilliant in the first half but United were brilliant in the second half.
Man Utd news: Marcus Rashford scored a late winner against Bournemouth on Saturday (Image: GETTY)
“It's just putting that 90 minutes together.
"I don't know why that is - as a United fan you are scratching your head.
"They have proven they can give anyone a game.
"If you don't turn up against Juventus or play for 45 minutes you will not win.