RB: Kieran Trippier (Tottenham)
Trippier's rise over the last few months has been absolutely mercurial. He was phenomenal at the World Cup, playing a pivotal role in England's run to the semi-finals.
He was rested for Spurs' win over Newcastle, but made a return against Fulham, and even scored a delightful free kick.
United have had problems at right back for a while now. Matteo Darmian was unimpressive against Leicester, and so was Ashley Young against Brighton. Valencia and Diogo Dalot are still recovering from injuries, making this a much easier decision.
CB: Davinson Sanchez (Tottenham)
There were question marks over Sanchez when Pochettino signed him from Ajax last summer, but he's proven to be an inspired signing for Spurs.
Against all odds, he displaced Alderweireld as the first choice centre back, and will probably start on Monday. He also enjoyed a productive World Cup with Colombia, playing in all four of their matches.
Eric Bailly and Victor Lindelof were decent against Leicester but were absolutely awful against Brighton, and based on current form, neither of them make it into this XI.
CB: Jan Vertonghen (Tottenham)
One of the best centre-backs in the Premier League right now, Vertonghen has played in both of Tottenham's matches so far in spite of some residual World Cup fatigue.
Its unsure whether Pochettino will opt for a 4- or 3-man defence at Old Trafford, but Vertonghen will certainly be one of the first names on his team sheet.
With Hugo Lloris recently being arrested for drunk driving, and with rumours about him being stripped of his captaincy, Vertonghen might even find himself leading Spurs out on to the pitch on Monday.
LB: Luke Shaw (Man Utd)
This is a close one between Shaw and Ben Davies, but the former narrowly edges out the Wales international on numbers. Shaw is ahead on duels won, tackle success rate, and passing accuracy so far.
In what has been a miserable start to the new Premier League season for Mourinho, Shaw has been one of the few positives to take away. The 23-year-old put in a lot of hard work in pre-season and is reaping the rewards now.
The former Southampton star's career at United hasn't gone according to plan, but if he puts in a good performance against Spurs, his future at Old Trafford might finally be in his own hands.