United are turning their attentions from Alvaro Morata to the Everton frontman , both of whom are also high on Chelsea's list of targets.
He has enhanced his reputation since then, with a forgettable spell at Chelsea which saw him granted limited game time erased from the memory bank after becoming a proven Premier League and international performer.
Belotti can only be signed if his €100m release clause is activated. The news of the Lukaku bid is force Real Madrid's hand.
Paul Pogba, however, is one of the main factors why Lukaku is keen on the move to Old Trafford.
Conte held talks with the Spain international about joining Stamford Bridge last summer but Madrid refused to sell.
Lukaku has made no secret of his desire to leave Ronald Koeman's side to play in the Champions League and compete for titles, but Everton have attempted to hold firm over the Belgium and insist a deal has not yet been struck.
Lukaku's previous association with Manchester United coach Jose Mourinho at Chelsea also comes as a huge plus for the club.
Missing out on the Belgian would place further strain on Conte's relationship with the Chelsea board, with the manager having been frustrated to date at the club's inability to add to his options.
He later took in a stint at Everton, where Lukaku has impressed over the course of the last four seasons with 87 goals in 166 appearances.
On Wednesday, Arsenal signaled its intention to make an immediate return to the English Premier League's elite by paying a club-record 60 million euros (US$68 million) to sign Lyon striker Alexandre Lacazette, one of Europe's most prolific players in recent years.