The Copa Libertadores final that Madrid had to host

The 2018 Copa Libertadores final was already historic before a ball was kicked. Boca Juniors against River Plate: the two biggest clubs in Argentina, the two biggest clubs in South America by most measures, meeting in the competition's final for the first time. The first leg finished 2-2 at Boca's ground. Then everything broke apart.

On 24 November 2018, the Boca team bus was attacked by some River supporters on its way to the Estadio Monumental for the second leg. Windows were broken. Police fired pepper spray. Several Boca players were taken to hospital. The match was postponed twice.

CONMEBOL then removed the second leg from Argentina altogether. President Alejandro Domínguez confirmed it would be played at the Santiago Bernabéu in Madrid, with supporters of both clubs admitted. Both clubs objected. So did their supporters and senior figures in Argentine football. Argentina's president, Mauricio Macri, called the original attack "a tough blow" and said it "must lead us all to reflection."

The match went ahead on 9 December 2018. River Plate won 3-1 after extra time, 5-3 on aggregate, and claimed their fourth Copa Libertadores title. A continental championship was decided on another continent, in a stadium belonging to neither finalist, in a country neither club plays in.

Marcelo Gallardo, River's coach, did not soften what had happened. "We're going to play the Copa Libertadores 10,000 kilometres away," he said. "Someday we're going to rethink what just happened, and we're going to remember this as a total embarrassment." Those words came from the man who won it.

The relocation was framed partly as a way to let both sets of supporters attend. In Buenos Aires, away supporters have been barred from Argentine league matches for years — the two clubs' fans cannot sit in the same ground for a domestic game. Madrid, in theory, changed that. Around 25,000 supporters of each club were expected at the Bernabéu. CONMEBOL set aside 5,000 tickets per club for supporters travelling from Argentina.

Neither club sold its full allocation. The unsold tickets went back to CONMEBOL. A journey of more than ten thousand kilometres, arranged at a few days' notice, in December, priced most of both supports out. About 4,000 police were on duty. The supporters of the two clubs who did make it sat alongside each other on the long sides of the stadium, and the match passed off peacefully.

The final was moved so both sets of fans could attend. Thousands of the seats reserved for them were returned unused.