Sevilla and Manchester United's war of words over Champions League tickets continues after the Premier League club raised their prices to match what their own fans must pay in Spain.
The two sides, who meet in the last 16 of the Champions League, are rowing over the cost for visiting supporters in each leg and Uefa are now set to become involved.
Travelling United supporters must cough up £89 each for February's first leg at the Ramon Sanchez Pizjuan, where Liverpool fans were charged £54 in November.
Not only have United responded by subsidising supporters the £35 difference, they have also increased the price for visiting fans at March's return leg at Old Trafford to £89 as well.
Sevilla insist they too will cover the additional sum for their fans and intend to contact Uefa over United upping costs and allocating them just 2,995 tickets in Manchester.
Uefa rules stipulate that at least five per cent of a stadium capacity's should be available to visiting supporters, yet Sevilla claim United have not offered them 3,800 tickets for security reasons.
Part of the statement on Sevilla's website read: "Sevilla FC will subsidise the price increase for club members travelling to Manchester.
"With this subsidy, the club will guarantee that no club members pay more than the 60 Euros (£53.15) initially specified.
"Sevilla will be in contact with Uefa over both Manchester United's failure to make five per cent of tickets available to away fans, as well as the club's price increase after a formal application for an away allocation.
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"Sevilla will also look to guarantee that no Sevillista pays a penny more than any Manchester United fan for similar tickets - as competition regulations dictate."
United's move to charge Sevilla supporters £89 came after attempts to persuade the Spanish club to lower their prices failed.
Supporters who have tickets for the game at Sevilla were informed by email that United would be refunding them £35, with that money raised from the price-hike for visiting fans at Old Trafford.
United pledged any extra revenue would be donated to the club's foundation.
Press Association Sport reports that United's head of ticketing and membership Sam Kelleher wrote in an email: "In this instance we believe that our travelling supporters are unfairly being subjected to increased/excessive ticket prices from the host club.
"This view is shared generally amongst travelling supporters, and we have received lots of requests from individuals and supporter groups to intervene in this matter.
"This has been raised with Sevilla, and internally, but ultimately Sevilla have not agreed to significantly lower the price of tickets for our fans to what we view as a reasonable level. Therefore we have taken the difficult decision to charge Sevilla fans for the return leg at Old Trafford the same amount as our fans have been charged for the away fixture.
"We have decided to increase the ticket prices for Sevilla fans for the game at Old Trafford, and use this increase to subsidise our fans, as we want this to act as a deterrent to future opponents who look to increase ticket prices for our travelling supporters."
The Manchester United Supporters Trust (M.U.S.T) praised the club.
"We have been working with the club since we became aware of the ridiculous £89 Sevilla (away) ticket price," the trust said in a statement.
"Our primary objective was to ensure our fans didn't end up paying this much. We are delighted United have fought our corner on this issue."
Additional reporting by the Press Association.