One tie stands head and shoulders above all others as the South American qualifying competition for the 2010 FIFA World Cup South Africa™ enters the fourth round of matches. Brazil and Uruguay, two of the game's oldest adversaries, go head to head in Sao Paulo, while Argentina face a challenging away day in Colombia and second-placed Paraguay travel to Chile. FIFA.com is here to preview some intriguing midweek match-ups.

A clash steeped in history
Brazil - Uruguay, Sao Paulo, 21 November, 21:45 (local time)

This classic South American football rivalry took on a whole new dimension 57 years ago when Uruguay famously defeated their hosts at the Maracana to claim their second FIFA World Cup™ Trophy. Ever since then the Brazilians have been driven by revenge whenever the two sides meet, while the Charrúas have always been keen to remind them of what they can achieve with their famed drive and commitment .

Collectively Brazil have disappointed so far on the road to the finals, relying instead on individual flashes of genius to pick up points. Opponents Uruguay, meanwhile, have been solid if a little inconsistent, the side effects perhaps of the transitional phase they are currently engaged in. Whatever the differences between the two, a compelling dogfight is in store between two direct rivals for a place in the South African sun.

Close-up: A question of stamina. After driving themselves hard against Chile on Sunday, Uruguay could struggle to contain a Brazil side who should be fresher from the weekend's exertions.

Head-to-head
: Uruguay's solid rearguard, marshalled by Diego Lugano, versus Brazil's offensive machine, spearheaded by Ronaldinho and Kaka.

Flashback
: Although Uruguay have never won a qualifying match in Brazil, they have come away with 1-1 and 3-3 draws on their last two visits.

The words: "History tells us that playing with three defenders away to Brazil would be a mistake." Oscar Tabarez, Uruguay coach.

Clean sheets at stake
Colombia- Argentina, Bogota, 20 November, 19.50 (local time)

Despite only hitting top form intermittently, Argentina have proved they are far and away the best side in the qualifying group to date, picking up maximum points from their three games. The foundations of Albiceleste success have been solid defence, the equilibrium provided by Javier Mascherano in midfield and the attacking variations offered by Juan Roman Riquelme and the explosive Lionel Messi.

Colombia's back line has been operating just as effectively as Argentina's, and keeper Agustin Julio has yet to pick the ball out of the net. Yet it is up front where the Cafeteros have come up short and worryingly for them striker Radamel Falcao is a major injury doubt ahead of Tuesday evening's tie.

Close-up: Agustin Julio and Roberto Abbondanzieri are the only two keepers yet to concede a goal in the competition.

Head-to-head
: Ruben Dario Bustos vs. Juan Roman Riquelme. Who will come out on top in the battle of the set-piece specialists?

Flashback
: Since the infamous 5-0 drubbing they suffered at the hands of Carlos Valderrama and Co in Buenos Aires in September 1993, Argentina have gone six qualifying games unbeaten against the Colombians, winning four - two of them away from home - and drawing two.

Elsewhere
Down in Santiago, Chile entertain second-placed Paraguay in another high-stakes encounter. Both sides are going into the game in fine fettle. La Roja rescued a vital point in Montevideo at the weekend, thanks in no small part to an excellent two-goal display from skipper Marcelo Salas. The visitors, meanwhile, put five past the hapless Ecuadorians. The question is, will Chile boss Marcelo Bielsa and his disciple Gerardo Martino call each other's bluff and name a three-man front line?

The final two games on matchday four involve four sides urgently in need of points. Venezuela play host to Bolivia on Tuesday evening in a match that will go some way to determining what the future holds for both sides. One thing is for sure, however: a draw will be of little use to either team. With the Vinotinto yet to pick up a point at home, and the Bolivians still pointless on their travels, something has to give.

Rounding off the week's action is crisis-stricken Ecuador's home meeting with Peru. For Victor Vizuete , the Tricolor's caretaker coach following Luis Fernando Suarez's demise, three points against the Peruvians could well see him keep the job. A determined Incaico outfit will be no pushovers, however, as they showed in a lively performance against Brazil. With Paolo Guerrero sitting the game out, can Claudio Pizarro bear the burden of leading the Peruvian attack?

This week's fixtures
Tuesday 20 November
Venezuela-Bolivia
Colombia-Argentina

Wednesday 21 November
Ecuador-Peru
Brazil-Uruguay
Chile-Paraguay

Standings
Argentina (9 pts)
Paraguay (7)
Brazil (5)
Colombia (5)
Uruguay (4)
Chile (4)
Venezuela (3)
Peru (2)
Bolivia (1)
Ecuador (0)