After losing just seven games in total in his two matches on Thursday, top seed Novak Djokovic was taken to the wire by Juan Martin del Potro in the quarter-finals of the Italian Open on Friday. Djokovic lost the first set and saved two match points in the second before prevailing 6-4, 7-6(8/6), 6-4. The world number one will face another Argentinian - Diego Schwartzman - in the last four.