The Daily Star says United will make a first and final bid of £90m for Sancho next week in the hope of landing the England sensation.
United are poised to offer Borussia Dortmund £75m up front plus £15m in add-ons in a bid to lure their No.1 target to Old Trafford.
It is understood United executive vice chairman Ed Woodward will make his move and make it clear to Dortmund it will be a take-it-or-leave-it offer.
The summer transfer window closes on October 5 and United bosses remain confident of signing Sancho.
Dortmund have been holding out for £108m for Sancho and their refusal to budge on the asking price has seen the saga drag out for almost three months.
But United are set to call their bluff and make the Bundesliga outfit an offer they believe is 'generous' given the football's financial downturn.