Ange Postecoglou defended his team selection after suffering his first defeat as Tottenham boss after Fulham won 5-3 on penalties following a 1-1 draw in the League Cup second round on Tuesday.
Postecoglou had masterminded an encouraging start to his first season in charge of Tottenham, with successive Premier League wins against Manchester United and Bournemouth following a draw against Brentford.
But the former Celtic boss paid the price for making nine changes to his starting line-up at Craven Cottage.
Postecoglou handed a full debut to Manor Solomon, while Giovani Lo Celso and Pierre-Emile Hojbjerg started despite speculation over their futures.
Fulham boss Marco Silva made six changes himself, but it was Tottenham's understudies who struggled.
Micky van de Ven's 19th-minute own goal gave Fulham the lead as the defender turned Tom Cairney's cross past keeper Fraser Forster.
Tottenham took advantage of a curious incident that left Fulham down to 10 men to equalise in the 56th minute.
But Tottenham were unable to find a winner and in the shoot-out Davinson Sanchez's effort was saved by Marek Rodak before Tete, now with boots on both feet, fired the decisive kick.
Currently enduring a trophy drought that stretches back to 2008, Tottenham already have one less competition in which to end that barren run this term.
Fourth-tier Salford, co-owned by former Manchester United stars David Beckham, Gary Neville, Ryan Giggs and Paul Scholes, beat Leeds 9-8 on penalties after a 1-1 draw with the Championship club.
Luton beat fourth-tier Gillingham 3-2 at Kenilworth Road to win for the first time this season.
Bournemouth boss Andoni Iraola earned his first win in English football as Ryan Christie's last-gasp goal clinched a 3-2 victory at second-tier Swansea.