Tottenham failed to score for a third consecutive Premier League game without striker Harry Kane in a 0-0 draw to Watford at Vicarage Road on Saturday.
The goalless draw means Spurs remain without a Premier League win since a 2-1 home victory against Brighton on Boxing Day.
A nicely weighted through ball from midfielder Dele Alli sent winger Lucas Moura though with the best opportunity to open the scoring in the half, but the winger missed the resulting one-on-one, forcing a save from goalkeeper Ben Foster.
The home side dominated in the opening stages of the second half, with Abdoulaye Doucoure unable to keep his shot on target from inside the six-yard box. Sarr, who regularly got the better of Spurs teenager Japhet Tanganga, went close moments after a poorly dealt-with cross fell to the winger who badly mistimed his volley.
Tensions, which at times threatened to boil over, came to a head when Doucoure and Spurs midfielder Harry Winks clashed deep inside the visitors' half, leading to multiple players from each side getting involved. Vertonghen went down holding his face, appearing to have been hit in the mouth, but referee Michael Oliver ruled that there was no serious foul play.
Spurs came within inches of a winning goal deep into stoppage-time after an Erik Lamela shot looked roll over the goal line following a short-lived scrap inside the Watford penalty area, but goal line technology ruled no goal.
"I think we played well, we started well and we finished well," Mourinho told reporters. "It's not easy to come here with a team that is technical, not physical.
"By one centimetre at the end we didn't win."
Information from Reuters contributed to this report.