Aided by an untimely leg injury to its opponent's top player, Argentina jumped out to a 2-0 lead in its opening- round Davis Cup tie with Germany following Friday's singles play.
The Germans appeared on the verge of gaining the upper hand in the best-of- five series after Philipp Kohlschreiber took a 5-4 edge in the fifth set of his bout with Carlos Berlocq. However, the world No. 19 was forced to retire just one game away from winning the match after pulling his left hamstring.
Kohlschreiber took the first set 6-3 before Berlocq, a fill-in for world No. 7 and former U.S. Open champion Juan Martin del Potro, rallied for a 7-5 decision in the second. Kohlschreiber rebounded for a 6-2 triumph in the third set, but Berlocq was able to extend the eventual four-hour match by taking the fourth by a 6-4 score.
Juan Monaco then put the Argentines one victory away from advancing to the quarterfinals after the world's No. 12 ranked player handled Florian Mayer 6-7 (4-7), 6-3, 6-3, 6-4 on the red clay of Parque Roca.
Kohlschreiber's status for the remainder of the event is yet to be known. He was scheduled to participate in Saturday's doubles match with partner Christopher Kas against the tandem of former Wimbledon singles runner-up David Nalbandian and Horacio Zeballos.
Berlocq, ranked 70th in the world, wasn't initially slated to participate in Friday's singles rubber, but got the nod after del Potro pulled out of the event while citing wrist soreness.
The winner in Buenos Aires will meet the France-Israel victor in April's quarterfinals, with the French currently owning a 2-0 lead in that tie.
Argentina also ousted the Germans in the first round of last year's Davis Cup, giving the nation a 6-2 advantage in the all-time series.