The biggest final in the world

Boca's La Bombonera stadium will be packed to its towering rafters for the first leg as the Buenos Aires rivals meet in the final of South America's Champions League equivalent for the first time.

"It's the dream final," said Argentina's former manager Marcelo Bielsa, who will watch from the safe distance of Leeds in England, whose club he now manages.

Known as the fiercest rivalry in world football, overshadowing the 'El Clasico' of Barcelona v Real Madrid, and those of Manchester City v Manchester United and Roma v Lazio -- River v Boca is known as the 'Superclasico'.

River will run out into the cauldron of La Bombonera with a slight edge, having beaten Boca 2-0 in a league game here in mid-September with goals from Gonzalo Martinez and Ignacio Scocco.

A key danger for River is the finishing of Dario Benedetto, who came off the bench in both legs of Boca's semi-final against Brazil's Palmeiras to score crucial goals.

River beat Brazil's defending champions Gremio with a late penalty in Porto Alegre, but the fireworks of that win continue to overshadow River.

- Manager banned -

Manager Marcelo Gallardo has been banned from even entering the Bombonera for the final. South American football body CONMEBOL punished him after he violated an earlier ban on communicating with his players by entering the dressing room -- in disguise -- during half-time of the fraught semi-final victory.

Gallardo had originally been given a touchline ban for delaying his team in the dressing room at half time in the home leg.

A few players will be walking a tightrope when the tackles fly in on Saturday. Yellow cards for midfield playmaker Pablo Perez, winger Cristian Pavon, the Uruguyan Nahitan Nandez and left-back Lucas Olaza would rule them out of the second leg on November 24 at River's Monumental stadium.

River have six players on yellow, notably the center-back pairing of Jonathan Maidana and Javier Pinola.

At 34, it's an extraordinary career finale for Boca's Carlos Tevez, who returned from a lucrative but injury-plagued stint in China to his boyhood team.

The ex-Juventus, West Ham and Manchester United star is struggling for pace these days but has big-match winning instincts and may be used off the bench.

- History of violence --

A history of violence between both sets of fans means that both legs will be played in front of home fans only as authorities see the risks, even for a showpiece such as the Libertadores final, as too great.

"I don't want to have a death on my hands," said River's president Rodolfo D'Onofrio. Boca's president Daniel Angelici agreed. More than 300 people have died in football-related violence in the last 50 years.

Tickets have been changing hands on the black market for up to $25,000 for the once-in-a-lifetime clash. The almost-vertical Bombonera will be packed to its noisy 53,000 capacity. "You would need three Bomboneras," said Angelici.

The return leg, at River's Monumental stadium on November 24, will be played before a full house of 67,000.

- Combustible mix -

Added to the combustible mix is that the derby is often pitched as a working class v middle class battle, with cries of treachery aimed at River -- once from the same Boca neighborhood as its rival -- for betraying its dockland roots in moving to the leafy Buenos Aires suburb of Nunez.

Boca have won six Libertadores since the competition began in 1960, twice as many as River, the most recent of whose victories came in 2015. Boca won the last of its Copas in 2007.

It will be the last final of its kind. From next season, the Libertadores will be decided in a one-off final on neutral ground.