The lads - with three wins in three before Saturday - lost 4-0 to the Blues in the FA Premier Academy League.
But it was a case of the scoreline not quite reflecting the game, as Academy manager John pointed out.
"We've had an opportunity to analyse the game and both teams had nine chances," he explained. "Both teams had five efforts on target, but they scored four goals and we didn't score once.
"It was an even game up to the penalty boxes and that's where we struggled on the day.
"It was disappointing to lose because we'd started so well but we'll have worst performances than that and win games."
Spurs U18s: Stroud, Smith, Dervite, Lake (Ntandari, 58), Hughton, Lewis, Livermore, Wells (Hutton, 46), Davis (Hutchins, 72), Pekhart, Maghoma. Unused sub: Button.
John McDermott reported that our Under-18s lacked the killer instinct as they suffered a first defeat of the season against Chelsea.