The Reds boss brought in Virgil van Dijk and Alisson and within two-and-a-half seasons won the Champions League and their first league title in over 30 years.
Meanwhile, United have added £80 million signing Harry Maguire, however, questions remain over his centre-back partner Victor Lindelof and their No. 1 David de Gea.
Jadon Sancho is believed in order to be Ole Gunnar Solskjaer’s priority target in the transfer window, however , the move has been blocked by Borussia Dortmund due to United’s unwillingness to pay their £108 million price tag for the winger.
Upamecano has been linked with a move to the Red Devils and Arsenal, but Leipzig recently moved to extend the particular Frenchman’s contract to 2023.
The 21-year-old powerhouse produced another excellent performance in the Bundesliga side’s 1-0 win over Atletico Madrid in the Champions League quarter-finals on Thursday.
Former Chelsea and Netherlands midfielder Gullit believes defence should be the priority for United within the transfer market and proposes that Upamecano could be a good option.
He told beIN Sports: ‘[What] Was the first thing [Jurgen] Klopp do with Liverpool?
‘He bought a great defence. He bought a goalkeeper and good defenders because everything starts there.
‘And I think Man United should start there as well. I saw something amazing with Leipzig and Dayot Upamecano.
‘He was outstanding [against Atletico Madrid]. He can play football, he’ s hard in the tackle
‘Defence is what I would start if I was Man Utd. ’
For more stories like this, check our sport page