Spurs defender Eric Dier was forced to leave the pitch midway through the second half to sprint to the toilet.
He was then followed down the tunnel by manager Jose Mourinho, who later said he was pushing Dier to get back on the pitch as quickly as possible.
Some fans wondered what Dier might have been up to in the changing rooms.
In an interview following the game, which Tottenham won 5-4 on penalties, Dier said that there was nothing he could do about it, as nature was calling.
It was Dier who had the last laugh, however. He was awarded the man of the match award, scored in the penalty shootout, and admirably consoled Chelsea midfielder Mason Mount after his miss sent Spurs into the quarter-finals.
