Buenos Aires (AFP) – South American champions River Plate and fierce rivals Boca Juniors meet Tuesday in a combustible Copa Libertadores semi-final, with the embers of last year’s all-Argentine final still smouldering.

The 2018 decider between the two Buenos Aires giants will be remembered for all the wrong reasons.

River won 5-3 on aggregate after the second leg was moved more than 6,000 miles (9656 kilometres) to Madrid to avoid a repeat of the fan violence that forced the postponement of the first leg.

Boca parted ways with coach Guillermo Barros Schelotto soon after. The man who replaced him, Gustavo Alfaro, has guided his side to an unbeaten start to the season in the Superliga. 

The two sides met for the first time since the final at River’s Estadio Monumental earlier this month, a tense 0-0 draw in the Superliga.

Alfaro will be hoping for at least a repeat in Tuesday’s first-leg at the same venue.

“It’s a 180-minute tie, and the idea is to be still in it when we take them back to Boca,” said Alfaro.

“You want to get through to win the cup, but if it was so easy, Boca wouldn’t have waited since 2007 to do it.”

Midfielder Eduardo Salvio is a doubt, with Alfaro likely to choose either Colombian Sebastian Villa or Franco Soldano to take his place.

River’s talismanic coach Marcelo Gallardo will be missing captain Leonardo Ponzio and will also have to plan without languid Colombian playmaker Juan Fernando Quintero, the hero of last year’s final. 

“It’s the first game and it’s important, but it won’t decide anything,” said Gallardo. “We’ll be looking to win, but if not we’ll have another chance. We’re dangerous away from home.”

Both came through tricky quarter-final ties, Boca impressively winning 3-0 away to Liga de Quito at altitude in Ecuador, before drawing 0-0 at home. River beat Paraguay’s Cerro Porteno 2-0, drawing a tough away leg 1-1.

Boca are the form side, unbeaten in the Superliga this season, while the Copa Libertadores champions are back in seventh place, having already lost twice. 

River beat Diego Maradona’s bottom club Gimnasia 2-0 at the weekend, while Boca drew 1-1 at home to Newells Old Boys.

The Monumental will be packed with 70,000 fans for the showdown, with the second-leg scheduled for Boca’s Bombonera stadium across the city next month.

Despite the history between these teams, the South American football federation will be hoping for an incident-free tie over the two legs, given the violence that marred their clash last year. 

The second leg had to be postponed twice after River fans attacked the Boca team bus as it arrived at the Monumental, and several Boca players needed hospital treatment for eye injuries caused by glass shards. 

Others said they suffered from smoke inhalation.

The violence ultimately caused the federation to shift the final to Madrid.

The other Libertadores semi-final on Wednesday is an all-Brazilian affair between Gremio and Flamengo. 

River’s triumph last year was the last two-legged Libertadores final. This year’s showpiece will be held in Santiago on November 23.