Indian Wells, California: Argentina's Juan Martin del Potro upset World No. 3 Andy Murray 6-7 (5/7), 6-3, 6-1 on Friday to reach the semi-finals of the ATP Indian Wells Masters.
Del Potro, the 2009 US Open champion, beat reigning US Open champion Murray for just the second time in seven meetings and booked a clash with World No. 1 Novak Djokovic for a place in the final.
Djokovic earlier remained unbeaten in 2013 with a 6-3, 6-1 victory over France's Jo-Wilfried Tsonga.