Argentine clubs have traditionally been the most consistent, and that seven of them have lifted South America's greatest prize indicates the quality in Argentina's domestic competition over the years has been of the highest standard.
However, the situation has changed somewhat in recent years. Argentine clubs may continue to be very competitive internationally while still producing world-class players, but their era of domination has clearly ended. Besides Boca Juniors, no other Argentine club has won the Copa Libertadores since River Plate did in '96, and none have even been finalists.
The lack of success in the current edition of the Copa Libertadores is an accurate reflection of their decline.
Even though five of Argentina's six representatives reached the final 16, their luck in the knock-out stages is quickly running out. On Tuesday night both Estudiantes de La Plata and Lanús were eliminated by Liga de Quito and Atlas, respectively, two clubs with no real tradition of success in the Copa Libertadores.
Estudiantes, which lifted its three continental titles almost 40 years ago, were expected to go farther. But Juan Sebastián Verón and company will be frustrated with an early exit, with Estudiantes' disastrous away form a primary culprit.
Meanwhile Lanús, which surprised everyone last year when it became Argentine champions for the first time in its 92-year history, has experienced a horrific change of fortune. Despite retaining the bulk of last season's championship-winning squad, Lanús is rock-bottom of the 20-team Argentine First Division. Compounded with an early Libertadores elimination, the club is clearly in a state of crisis.
But what should pose the greatest concern for Argentine soccer is that their domination has been snatched away by their archrivals Brazil. Six Brazilian clubs have lifted the title since '95, and the trend is likely to continue this year, with Fluminense, Flamengo and Santos looking stronger than ever.
The track record of Brazilian clubs in this year's Libertadores has been simply amazing. All five of its teams cruised into the last 16, and they all have great possibilities of joining Fluminense in the quarterfinals.
Flu's Rio de Janeiro rivals Flamengo have all but sealed their spot in the next round after picking up a massive 4-2 victory over Club América in Mexico City last week, while São Paulo and Cruzeiro's chances of advancing are intact. Any win for São Paulo over Nacional at the Morumbí will do, while Cruzeiro only need a narrow home victory over Boca to advance.
Santos should also close in on a quarterfinals appearance when they take a comfortable 2-0 advantage into the return leg of their tie with Cúcuta Deportivo in Colombia on Thursday.
The same can't be said for the Argentine contingent. Its only chances lie with three of its top Buenos Aires clubs: Boca, River and San Lorenzo (the last two are up against each other in the last 16). River, who hasn't managed to even win a domestic title in eight short seasons, needs to overcome a tricky 2-1 deficit at the Monumental stadium on Thursday to advance.
But Los Millonarios have to be extremely cautious to knock off a superb San Lorenzo side, which have won a whopping 13 of their past 15 matches in both league and Libertadores play. Team coach Ramón Díaz has assembled a formidable unit that has benefited from Andrés D'Alessandro, Juan Manuel Torres and Gonzalo Bergessio finally hitting top form.
If any Argentine club is to challenge for the title along with the Brazilians it will surely be Boca. Los Xeneixes have won four of the last eight editions of the competition and have clearly demonstrated that they are a club that rises to the big occasion. For over a decade now Boca has been the only Argentine club who has found great success internationally, and they are always considered a serious threat.
Despite only taking a 2-1 lead to Brazil for the return leg of its tie with Cruzeiro, Boca has the necessary depth to return to Buenos Aires with a smile. Its superclásico victory over River Plate in the Clausura Championship last Sunday should be a great boost for the side as it looks to stay in contention for back-to-back Libertadores titles.
However, Boca will need to sharpen up as a defensive unit if it wants to overcome Cruzeiro in front of 70,000 roaring fans in Belo Horizonte. Carlos Ischia's side has conceded 10 goals in seven Libertadores matches, and its defensive frailties will surely be tested by Cruzeiro and top scorer Marcelo Moreno. That Boca has yet to win away from home also plays in its disadvantage.
Argentine soccer has experienced dramatic changes in recent years, with its international status being limited to the achievements of a single club. Boca Juniors has won several titles during this difficult period, but the nation's reliance on them suggests that Argentine soccer isn't as competitive as it once was. It is up to River Plate and San Lorenzo to buck the trend.