Virtual cousins, the two nations often quarrel politically and even soccer friendlies do not escape the need by both sides to assert their superiority on the pitch.
Diego Maradona's Argentina have only to draw to secure automatic passage to the South Africa finals. Uruguay, fired up by two life-saving wins over Colombia and Ecuador, must win.
That need is exacerbated by the fact that if Ecuador win their last match away to a Chile team who have already qualified, Uruguay will be left with nothing if they get no more than a point against Argentina.
Coach Oscar Washington Tabarez was quick to ensure his players kept their feet on the ground after their 2-1 win away to Ecuador on Saturday, saying the job was not yet done.
"We must re-group and concentrate absolutely on the match against Argentina...Our situation demands that because we don't have much credit, we depend exclusively on a win," Tabarez told reporters in Quito. Maradona, using typically apocalyptic language, said: "We're going to be giving our lives in Uruguay to qualify."
Four years ago Uruguay won 1-0 against an Argentina side who had already qualified comfortably, securing the playoff berth but then losing out to Oceania winners Australia. Four years before that, Uruguay had beaten Australia in the playoff.
JUGGLING ACT
Maradona's team selection has been a juggling act of names, hoping they will resolve his lack of team strategy, like sending Martin Palermo on in the second half against Peru on Saturday to secure victory.
"I'm thinking of some changes...how I insert Veron in the team," Maradona said. Midfielder Juan Sebastian Veron was suspended for the Peru match.
Pablo Aimar had moments when he gave Argentina some shape in attack and set up Gonzalo Higuain's opener early in the second half.
But Argentina ceded territory and often the ball to Peru, especially when Martin Demichelis came on for Higuain in the 67th minute to bolster a weak defence and succumbed to a 90th-minute equaliser before Palermo's stoppage-time winner.
Maradona said he did not intend to field Higuain and Palermo together from the start, no doubt thinking he might need to keep the 35-year-old Palermo fresh for another saviour's act.
The rivalry between Argentina and Uruguay - with more than 170 meetings including friendlies - began in 1901.
It reached heights in the amateur era with Uruguay's 2-1 victory over Argentina in the replayed 1928 Olympic final in Amsterdam followed by their 4-2 win over their great rivals in the first World Cup final at the Centenario in 1930.
In their only other meeting at the World Cup finals, in Mexico in 1986, Argentina, captained by Maradona, won their second round match 1-0 on their way to lifting the country's second title, emulating Uruguay.
