European champions Paris St-Germain produced a superb late recovery before winning a penalty shootout to clinch the Uefa Super Cup and deny Thomas Frank a first trophy as Tottenham boss.
Spurs led 2-0 after 84 minutes and were then seconds away from clinching an impressive victory before PSG substitute Goncalo Ramos headed in a 94th-minute equaliser.
That took the tie straight to penalties and PSG missed their opening effort as Vitinha fired wide, but Micky van de Ven, who had scored Tottenham's first goal earlier on, had his spot-kick saved by Lucas Chevalier.
Mathys Tel shot wide for Frank's side before Nuno Mendes held his nerve to convert the winning penalty for PSG.
It meant Tottenham missed out on winning a second European trophy in three months.
Frank was taking charge of Tottenham in a competitive match for the first time since he replaced Ange Postecoglou, who was sacked 16 days after guiding the club to a 1-0 victory over Manchester United in the Europa League final in May.
Van de Ven put Tottenham ahead in Udine, Italy, reacting first to slide in the rebound after Chevalier had tipped Joao Palhinha's effort on to the crossbar just before half-time.
Chevalier - expected to be PSG's regular goalkeeper this season after Gianluigi Donnarumma was surprisingly left out of their squad - was beaten again early in the second half when he got two hands to Cristian Romero's header following Pedro Porro's free-kick but could not keep the ball out of the net.
But PSG, who only returned to training a week ago after losing to Chelsea in the final of the Club World Cup in the United States in July, fought back in style.
Lee Kang-in started the recovery with an excellent strike from 20 yards, before Ramos dramatically took the tie to a shootout with PSG triumphing.