An opponent that cannot be beaten or overcome.

The aforementioned definition for the word nemesis could easily be followed by an example involving Adriano Leite Ribeiro and Argentina. The striker's 11th-hour equaliser took the Copa America 2004 final on to a penalty shootout, from where the Seleção overcame the Albiceleste, and his double imbued Brazil to a memorable 4-1 victory over their arch-rivals in the FIFA Confederations Cup Germany 2005 decider.

Adriano's status as Argentina's carrasco (hangman) could stand trial in front of over 60,000 witnesses tonight at the Estadio Mineirao, Belo Horizonte, where South American football's two superpowers will collide on Matchday 6 of CONMEBOL qualifying for the 2010 FIFA World Cup South Africa™. For after overcoming problems with form, fitness and alcoholism, O Imperador (The Emperor) is firmly back in the plans of the coach who warned him to "change his behaviour".

Dunga's words were heeded. Seventeen goals in 28 games during an impressive spell on loan at Sao Paulo from Inter Milan, one which has just come to an end, pay testament to this. This prolificacy was facilitated by Adriano's decision to quit partying and get himself into, according to Brazil's fitness trainer Paulo Paixao, "great shape".

Lasting memories
Gone is the unfit, unfocused, forlorn figure that Adriano had cut. Back is the hulking, hungry, fearsome competitor as capable of scoring left-footed piledrivers from outside the penalty area as he is of snapping up tap-ins. This versatility helped the Flamengo revelation score 25 times in his first 36 internationals, and it is something against which Argentina have suffered.

He broke the deadlock in the Germany 2005 final after cutting inside his marker and arrowing a thunderous shot into the top corner, and he then added his country's fourth and last goal with a close-range header. This inspirational performance helped Adriano walk away from the FIFA Confederations Cup with its adidas Golden Ball and adidas Golden Shoe awards, but he does not consider it his greatest display against Argentina.

This, he feels, came in the climax to the continental finals in 2004, when an under-strength Brazil were just seconds away from a 2-1 defeat to their neighbours. Without Kaka, Ronaldinho and Ronaldo, the then-reigning world champions found a hero in Adriano, who skilfully flicked the ball up inside a crowded area and volleyed it into the bottom corner of Roberto Abbondanzieri's net. The Rio de Janeiro native then stroked home his side's first spot-kick en route to a 4-2 shootout success and their seventh Copa America crown.

"The game of my life was against Argentina in the final of the Copa America," he said recently. "I scored a goal right at the end. If I hadn't scored it we would have lost the title. When we won [the penalty shootout] it was so emotional, everybody cried afterwards. This memory will stay with me forever."

How dearly Brazilians yearn for another Adriano master class tonight. Currently occupying fourth place, the last automatic qualification position to South Africa 2010, they desperately need to rebound from an insipid 2-0 loss away to leaders Paraguay on Sunday.

"A win against Argentina would wipe out this result," according to Adriano, who does want to contemplate achieving anything less. " in any which way."

The rivalry is huge, everybody knows this. I never want to lose to

Adriano on the rivalry between South America's two superpowers.

Adriano came on as a second-half substitute against Paraguay, and despite clamour for his inclusion from the start at the Mineirao, it is not yet known whether Dunga will give him the nod or maintain the Robinho-Luis Fabiano partnership against Alfio Basile's side. "As a player you always want to make the starting line-up. I'd like to be given the nod and to show what I can do but if I'm called upon to come off the bench, I'll be ready," said the 26-year-old, who also helped Brazil undo their fierce enemies 1-0 during their charge to the South American U-20 title in 2001.

"It's such an important game. Thankfully I've always done well against Argentina and I hope this continues. It would be great to score a goal and help the Seleção win - there's nothing better than beating Argentina."

If he does emerge as the Albiceleste's nemesis once again, the Emperor could well assume the throne reserved for Brazil's first-choice striker.