Serbian superstar Novak Djokovic registered a swashbuckling win over tall American John Isner in front of a howling crowd to clinch the tie for host nations here in Belgrade against multiple time champion, the USA.

Djokovic opened the match under tight circumstances but managed to break Isner in the 12th game to seal the opener 7-5. The second set saw an immediate role reversal when Isner broke Djokovic early on to level the match at one set a piece.

The story was repeated in the third and fourth set when both players tested each other to limits and forced a decisive fifth set which Djokovic won with the help of a golden break to complete the 7-5, 3-6, 6-3, 6-7, 6-4 win after marathon struggle.

With the win, Serbia made it to the quarterfinals with an invincible 3-1 lead. The victorious Serbians were later joined by the mighty Argentines, who overcame the Swedish challenge with a 3-2 tie win. In the first reverse singles today, Swedish No.1 Robin Soderling edged past Argentine Leonardo Mayer 7-5, 7-6, 7-5 to square of the tie score at 2-2.

In the decisive fifth rubber then, Davis Cup hero David Nalbandian exceeded all expectations and registered a hard fought 7-5, 6-3, 4-6, 6-4 win over Andreas Vinciguerra to give Argentina a place in the last eight.