Tottenham assistant head coach Cristian Stellini apologised to the club's fans after they were dumped out of the FA Cup by Sheffield United.
Blades substitute Iliman Ndiaye's solitary second-half strike clinched the Sky Bet Championship promotion-chasers a home quarter-final tie against Blackburn.
Tottenham's wait for a major trophy continues - they won the League Cup in 2008 - and they have now exited the FA Cup at the fifth-round stage three times in the last four years.
Head coach Antonio Conte missed his side's latest exit as he recovers from gallbladder surgery and Stellini said: 'I think we missed a big opportunity and we have to apologise to the fans.