The Daily Mail says United chief executive David Gill returns from holiday today to take charge of the champions' attempts to persuade Spurs to sell their Bulgaria striker.
United have already had a £20million bid rejected but boss Sir Alex Ferguson is determined to sign Berbatov, knowing the player is desperate to complete his dream move to Old Trafford.
Ferguson is also aware that neighbours Manchester City had a bid of £32m for Berbatov rejected in May.
However, the United manager is confident that, given the striker's burning desire for a return to Champions League football, an offer of around £25m will persuade Spurs to do business, with the fee possibly rising to £30m with performance related add-ons.
Ferguson will now leave the haggling to Gill while he takes charge of United's pre-season trip to South Africa on Wednesday.