Spurs were temporarily undermanned due to Dier's absence. He told AP their tight schedule recently may have contributed to his lavatory needs.
"Maybe that's one of the reasons I had to run off the pitch in the second half. He (Mourinho) wasn't happy but there was nothing I could do about it, nature was calling," he says. "After playing on Sunday and tonight it wasn't easy."
Despite his clear priorities of the bathroom over the ball, Dier was named man of the match.
His return may very well have paid off for the North London club, who went on to equalise in the 83rd minute through Erik Lamela, before outlasting their cross-town rivals 5-4 on penalties at White Hart Lane, and advance to the quarter-finals.
The hectic schedule does not quieten down anytime soon for Spurs, who have two games within the next five days.
