Defending champions Serbia will be huge favourites to reach the Davis Cup semi-finals this weekend as newly-crowned Wimbledon [ Images ] champion Novak Djokovic [ Images ] returns to action against Sweden.

Even without Djokovic, Serbia would be massively fancied in Halmstad where Sweden are without World number five Robin Soderling [ Images ] who is resting a foot injury.

Djokovic, who rose to world No1 for the first time this week, will play Friday's second singles match against fellow 24-year-old Ervin Eleskovic who is 344 places below him on the ATP standings. Viktor Troicki, ranked 16 in the world, opens against lowly-ranked Michael Ryderstedt.

In the pick of the quarter-final ties, the United States host Spain in Austin, Texas, home of their former world number one Andy Roddick [ Images ].

Roddick is joined by new US number one Mardy Fish [ Images ] and Wimbledon doubles champions Bob and Mike Bryan [ Images ] against a Spain side who will be without 10-times grand slam champion Rafa Nadal [ Images ] but still boast world number six David Ferrer and Fernando Verdasco [ Images ].

Last year's beaten finalists France [ Images ] travel to Stuttgart to play Germany [ Images ].

Argentina's last eight match against Kazakhstan began on Thursday because of weekend elections in Buenos Aires with the home side already 2-0 up.

Should they win Friday's doubles rubber they will secure a likely semi-final clash with Serbia.