Spurs attracted a record crowd of 85,011 to Wembley for their Group E opener against the French club with an air of expectancy around English football's headquarters.
Monaco delivered early when Fabinho closed down Erik Lamela's pass which fell to Bernardo Silva who drove into the area before unleashing with a left-footed effort into the left corner to kick things off for Leonardo Jardim's outfit.
Spurs had a great chance to equalise minutes later but Harry Kane shot straight at Subasic before Alli volleyed wide at the death to condemn Spurs to a home defeat in their top flight European return.
Despite the negative result, the attendance numbers gave Spurs their highest ever home crowd, the highest home attendance for an English club in the Champions League and there highest English club home attendance overall.
2016/17 UEFA Champions League - Group E
Wembley Stadium, London, England - 85,011