20-time Grand Slam champion Roger Federer needs just one win to displace rival Rafael Nadal as the world number one in the men’s ranking after he booked his place in the Stuttgart Open semi-final with straight sets victory over Guido Pella in their last eight duel.

The Swiss tennis legend defeated the Argentine world number 75 6-4 6-4 in 67 minutes in Stuttgart to book his spot in Saturday’s semis and a 14th consecutive grass-court win.

The 37-year-old will now face Nick Kyrgios of Australia in the semi-finals on Saturday, after the controversial tennis star saw off Feliciano Lopez of Spain in three sets.

He defeated his opponent 6-4 3-6 6-3 to setup a last four meeting with top seed Federer.