Giggs turns 40 today (29 November) and is showing no sign of physical deterioration, although his training schedule is tailored to get the most out of him, and most recently he turned in an eye-catching display against Bayer Leverkusen in the Champions League.
Berg, who played alongside Giggs between 1997 and 2001, is confident he can prolong his illustrious career thanks to advancements in sports science and also admits that he wouldn't be surprised if the Welshman signed yet another contract extension at Old Trafford.
"Ryan is obviously a different player now compared to when he broke through as a 17-year-old winger, but that says a lot about how football has developed in terms of sports science to make sure that players still have enough power and energy to play the physical part of the game," Berg told ManUtd.com.
"To be fair, last season he looked fitter than he did two or three years ago. That is a great achievement. He has a lot of help at the Aon Training Complex, but the biggest reason is his own mind, making the right decisions on and off the pitch. He has been fantastic.
"The way that football has developed, the central midfielder doesn't have to run from box to box or more than other players.