Daniel Levy stepped in to stop striker Emmanuel Adebayor leaving Tottenham for West Ham on transfer deadline day.
The Spurs chairman refused West Ham's bid to seal the loan deal after the 30-year-old Togo striker had agreed terms.
Tottenham were open to allowing him to leave during the transfer window and were prepared to subsidise more than half of his £100,000-a-week wages.
But they refused to extend those terms to West Ham, because they deemed them direct rivals.
Senior officials from both clubs were in talks until 23:00 GMT on Monday.
West Ham co-chairman David Gold apologised to fans after deals fell through having raised hopes of additions.
"Don't go to bed. DG," tweeted Gold during Monday evening.
But after the deadline passed without any new recruits, he added: "Sorry for keeping you up late but at the last moment the main deal collapsed and the rest folded like a pack of cards."
He thanked co-owner David Sullivan and manager Sam Allardyce for their efforts, blaming the Premier League club's failure to land new players on "people out there that you just can't do business with".
The collapse of the Adebayor deal had a domino effect, with the Hammers then blocking Carlton Cole's move to West Brom as they feared a lack of striking cover.
West Ham and Spurs have been in dispute in recent years over the use of the Olympic Stadium, which will be the Hammers' new home from the 2016-17 season.
QPR also made an enquiry for former Arsenal and Manchester City player Adebayor, who was not willing to join the Loftus Road club and will now attempt to force his way back into manager Mauricio Pochettino's plans.