Tottenham's Europa Conference League hopes hang in the balance after they suffered a humiliating 2-1 defeat against Mura on Thursday.
Amadej Marosa scored a dramatic stoppage-time winner as 10-man Spurs were beaten for the first time under Antonio Conte.
Prior to Marosa's heroics, the Group G contest had appeared to be heading for a stalemate with Harry Kane cancelling out Tomi Horvat's first-half strike at Fazanerija.
The much-changed visitors, who were a man light for over an hour in Slovenia after Ryan Sessegnon was sent off for two bookable offences, now need to beat Rennes in two weeks' time to guarantee second place.
Full-time. pic.twitter.com/olfS2k8Ihs— Tottenham Hotspur (@SpursOfficial) November 25, 2021
Mura, who arrived in the contest as one of only three teams yet to register a point in the inaugural competition, took the lead in the 11th minute.
Collecting the ball on the right flank, Horvat cut into the penalty area before bending a beautiful shot past a flat-footed Pierluigi Gollini.
Tottenham's task became harder as they were reduced to 10 men just after the half-hour mark – Sessegnon shown a second yellow card for a rash challenge on Ziga Kous.
Kane shot just wide on the turn, while Nik Lorbek was inches away from doubling the hosts' lead at the other end as both sides went close before the break.
Conte introduced Son Heung-min after the restart and the South Korea international drew a smart save out of Matko Obradovic following a brilliant individual run.
But Spurs were not to be denied in the 72nd minute, with Kane latching onto Lucas Moura's neat throughball before delicately lifting it over the advancing Obradovic.
Nevertheless, there was to be one final twist in the fourth minute of stoppage time. Mura launched a devastating counter that culminated in Marosa's strike deflecting home off Davinson Sanchez from the final kick of the game.