"This United squad are probably even stronger than 1999," he told the Daily Mail. 'We were the first generation of players who were rotated.
"Fergie foresaw that the game was becoming harder and was a step ahead of other people in wanting four top strikers so he could freshen things up. Since then he's taken it even further. He's got quality understudies in nearly every position.
'We also had a never-say-die attitude. It was about Peter Schmeichel's desire to save a penalty from Dennis Bergkamp in the FA Cup semi-final, to dig deep in the Champions League quarter-final against Inter Milan."
Sheringham added that United's "will to win" will see them fight for all competitions.
"I see it in this United team," said the 46-year-old. "I watched their FA Cup game against West Ham on TV.
"They weren't playing well and you couldn't see any way back. Then [Ryan] Giggs plays a pass to [Robin] van Persie - what a ball - and they're still in it.
"Whatever side Fergie puts out, they play like he manages. The will to win has been with him for more than 25 years and it is amazing how he does it. We did the treble so why can't anyone else? They are outstanding."
United are currently four points clear at the top of the Premier League table.