Celtic run of misery was compounded on Saturday by a red card for Ambrose – his second this week, having been dismissed in Wednesday’s Champions League qualifier against Legia Warsaw.
Roberto Soldado and Erik Lamela were among the goalscorers as Tottenham thrashed a largely second-string Celtic side 6-1 in Saturday’s friendly in Helsinki.
Spurs raced into a 2-0 lead thanks to efforts from frontmen Harry Kane and Soldado in the fourth and 11th minutes respectively.
Good work from Andros Townsend saw the winger beat John Herron for pace before cutting the ball back for Kane, who fired past Craig Gordon for the opener.
Slick passing from Spurs sent Lewis Holtby free, and Soldado’s initial effort from the German’s pass was saved at point-black range by Gordon, who was unlucky to see the Spaniard net the rebound.
Jamie Lindsay pulled a goal back for Celtic in the 43rd minute, after he headed Dylan McGeouch’s chipped pass beyond Brad Friedel, after the American had saved from McGeouch moments earlier.
Sixty seconds later Lewis Holtby restored the two-goal cushion, rifling home from Etienne Capoue’s pinpoint pass, and Tottenham kept the momentum going after the break.
Midfielder Lamela – who, like Soldado, is looking to bounce back after a disappointing first season with the London club – made it 4-1 just before the hour mark with a deflected shot off Connor McManus.
Christian Eriksen made it five with a well-taken free kick, after Efe Ambrose was penalised for bringing down Emmanuel Adebayor.
Adebayor himself hit the post after connecting with Aaron Lennon’s cross, before Ambrose was adjudged to have felled Danny Rose in the box, with the Togolese striker converting the spot-kick to make it six.