Chairman Daniel Levy has reportedly made it clear that he will reject any approach from their Premier League rivals as they search for a permanent appointment.
Interim boss Ole Gunnar Solskjaer is keen to succeed Jose Mourinho full time and has won his first five games ahead of Sunday's trip to Wembley.
However the Argentine remains the first choice of the United hierarchy and faces a potential audition this weekend.
Levy, though, believes that Spurs cannot risk losing Pochettino and will rebuff any advances from Old Trafford, according to The Sun.
They claim that even if United pay the final four years of Pochettino's £34m deal at Spurs, and an additional £16m, Levy will stand firm
The chairman also appears willing to give the manager the last word on all transfer activity.
Tottenham could find themselves nine points behind Premier League leaders Liverpool when they kick-off against United on Sunday afternoon.
United are six points adrift of the top four as they chase Champions League qualification for next season.