The protracted battle for control of Sky looks increasingly likely to be decided by auction after Fox followed rival bidder Comcast in extending the deadline on its offer for the pay-TV giant.

Comcast has lodged the higher bid for the U.K.-based business, at £14.75 ($19.41) per share. Fox, which already owns 39% of Sky, has offered £14 per share. On Monday, Fox extended the deadline for Sky shareholders to accept its current offer to Oct. 6, the same day as Comcast’s deadline.

“Sky shareholders who have not yet accepted [our] offer are urged to do so as soon as possible,” Fox said in a statement filed with the U.K. Stock Exchange.

Fox did not signal any intention to increase its bid, although it has until Saturday to do so. Sky’s board has backed Comcast’s richer offer, but fewer than 1% of Sky shareholders have so far opted for either side.

The deadlock paves the way for an unusual auction run by the U.K. Takeover Panel, which will see a definitive winner in the battle for control. The framework for the auction – its duration, the number of bids allowed, whether the bids will be made public – is reportedly under discussion by the panel, Comcast and Fox.

In a quick-fire faceoff, Fox starts with the considerable advantage of already controlling 39% of Sky shares, meaning that it would only have to persuade the holders of another 11% of Sky’s shares, plus one extra, to emerge the victor. Comcast, by contrast, must achieve 50%-plus-one from zero.

Fox has fought hard to get its offer for Sky approved by U.K. regulators in the face of stiff opposition. It has agreed to a raft of measures including handing the stewardship of the Sky News channel to Disney.

Disney, in turn, is in the throes of buying a raft of Fox’s entertainment assets, including its stake in Sky, having beaten off competition from Comcast.