Argentina and Croatia split a pair of singles matches in a best-of-five Davis Cup quarterfinal affair on Friday.

Martin Cilic gave the visitors the first point of the weekend by outlasting former Wimbledon runner-up David Nalbandian 5-7, 6-4, 4-6, 7-6 (7-2), 6-3 in an epic 5-hour, 9-minute war of attrition.

The world No. 23 Cilic popped 10 aces, while the 50th-ranked former top-five star Nalbandian piled up 11 double faults. The two men combined for 241 unforced errors, including 128 from the winner on the red clay at Parque Roca.

Juan Martin del Potro knotted up the series at one match apiece later on with a decisive 6-2, 7-6 (9-7), 6-1 dismantling of Ivo Karlovic in a tidy two hours, 19 minutes.

Del Potro, the U.S. Open champ in 2009, launched 10 aces while 6-foot-10 Karlovic recorded 53 unforced errors.

Saturday's doubles in Buenos Aires is supposed to pit an Argentine tandem of Nalbandian and Eduardo Schwank against a Croatian pairing of Cilic and Lovro Zovko, while Sunday's reverse singles have the world No. 10 del Potro taking on Cilic and the oft-injured Nalbandian facing the towering 52nd-ranked Karlovic.

The Argentines also have world No. 16 Juan Monaco at their disposal this weekend.

Argentina is 2-0 all-time versus Croatia, with both victories coming in quarterfinals (2002, 2006).

The tough-luck Argentines are captained by Martin Jaite, while team Croatia is guided by Zeljko Krajan.

Argentina is a four-time runner-up and still seeking that elusive first-ever Davis Cup championship. The Argentines lost to mighty Spain in last year's final in Seville and have lost in three of the last six Davis Cup finals overall.

Croatia captured its lone Davis Cup title back in 2005.

The Argentina-Croatia winner will meet the Czech Republic-Serbia victor in the semifinals in September.