Real Madrid have confirmed the departure of Marcos Llorente to fierce rivals Atletico.
The deal, thought to be worth £35million, was announced on social media and plenty of Real fans vented their frustration.
They were furious at not only losing the promising 24-year-old midfielder, but allowing him to join Diego Simeone's side across the city.
One fan wrote: 'Marcos was literally one of the best players last season!'
Another added: 'Sold such a promising lad to a direct rival? I hope there's a good reason behind selling him.'
A third predicted that withing a couple of seasons Llorente's value will have skyrocketed to £100m.
The announcement was confirmed on both club websites. Real wrote: 'Real Madrid and Atlético Madrid have reached an agreement over the transfer of Marcos Llorente.
'The club wishes to express its gratitude for the commitment and professionalism shown by the player over the years and for the exemplary conduct he displayed since he joined our academy in 2008 through until his time as a member of the first-team squad.
'Real Madrid wish the player all the very best in this new chapter.'
Atletico added: 'We welcome a great football player and wish him the best of luck in this beautiful and new challenge defending the shirt.'
There were a number of offers for Llorente on the table but Atletico was his preferred destination despite a reluctance from Zinedine Zidane to sell to Simeone's side.
Rodri is expected to leave Atletico and Llorente is viewed as the perfect replacement.
The deal also helps Real recoup some of the £344m they have already splashed out on Eden Hazard, Ferland Mendy, Rodrydo, Eder Militao and Luka Jovic.