Following a poor run of results, Mauricio Pochettino's side face an uphill struggle to climb back into the league's top four, having slipped to sixth in the table, and a massive 18 points behind league leaders Manchester City.
And now defender Vertonghen accepts Tottenham have serious work to do to set their league season back on track.
"We have to get back to winning ways and we know that," said Vertonghen. "We had a run where we had to win a couple of games and we didn't so I suppose the pressure is a little bit more, but we know we can win these games."
Meanwhile, full-back Kieran Trippier also insisted Tottenham remain unfazed by their recent run.
Asked if Spurs feel any concerns over their winless run, Trippier replied: "No, of course not. We've got a fantastic team, great spirit, a hungry young team and a great manager - we just have to keep going.
"It was difficult when we went down to 10 men but we still created chances and kept pushing on for the three points. We had to dig deep. Watford are a good side and they played well."