The frustration at having been denied a victory in Monday's fourth-round tie by a controversial late penalty has at least been tempered by the financial boost from next week's replay at Stamford Bridge.
Although only 3,000 Oxford fans will be allocated seats, gate receipts mean the struggling First Division side may earn pounds 200,000 from the replay.
They have already received a similar amount from the televised game at the Manor Ground and the income represents a massive boost.
Oxford had been in danger of going out of business only a couple of months ago and had to avert that possibility by selling the goalkeeper Phil Whitehead to West Bromwich and Simon Marsh to Birmingham, both for pounds 250,000.
With the side dangerously near the foot of the First Division and other clubs reportedly ready to make cut-price bids for players such as the leading scorer Dean Windass, having to sell more players could have sealed their relegation.
But Cox insisted: "We should receive about pounds 400,000 from the two games against Chelsea, especially if there is a full house at Stamford Bridge. That makes a huge difference to us in terms of our ability to meet our liabilities. Before the two games, it was certainly a possibility that we would have had to sell another player but that is no longer an issue." The long-term survival of the club still rests on finding an investor to fund a move to a half-built new stadium three miles away from the current outdated ground.
Cox envisages some progress being made on that front next week, although he realises that, without finding the finance and setting a completion date for building work, the future is bleak.
Meanwhile, Oxford still have the option to ask the Football Association to replace referee Mike Reed, who awarded the controversial penalty, for the replay at Stamford Bridge.
No talks have yet taken place at the club on the subject although there is continuing disquiet following that decision and the red card he issued to Oxford's Martin Gray in the FA Cup at Leeds last season.
However, it is unlikely that the FA would accede to any such request, unless it also had backing from Chelsea.
The Oxford striker Kevin Francis, who was deemed to have committed the foul on Vialli that led to the penalty, said he did not have a chance to speak to the Birmingham official after the game. He joked: "No doubt I'll catch up with Mr Reed in Birmingham, as I still live there, and we'll see what happens if I do."Reuse content