Tyson Fury has urged Anthony Joshua to "give British fans what they want" and sign a contract for a heavyweight world-title fight in December.
WBC champion Fury, 34, had given fellow Briton Joshua, 32, an ultimatum to sign by Monday, but said on social media he has extended the deadline to Thursday.
Joshua's promoter Eddie Hearn said there was "no chance" the contract would be signed by Monday.
"The ball is in your court, everything is done," said Fury.
"We have [broadcasters] BT, DAZN and ESPN all on the same page, they're happy with everything.
"If you have any dignity and pride about you, you'll get this contract signed today.
"I'm chucking you a massive bone but I know I can punch your face in so I'm willing to give you an opportunity. Let the British fans have what they want."
Joshua's team have already verbally accepted Fury's offer of a 60-40 purse split for a fight on 3 December, and television executives from BT Sport and streaming service DAZN were scheduled to meet on Monday.
Last month Joshua failed to regain the WBA (Super), WBO and IBF belts in a rematch with Oleksandr Usyk, losing on a split decision.
Ukrainian Usyk, 35, said he plans to have three more fights before retiring, including a unification bout with Fury, but Joe Joyce is now the mandatory challenger for Usyk's WBO title after beating Joseph Parker on Saturday.
Fury's last fight was a sixth-round knockout victory over fellow Briton Dillian Whyte in April.