Nadal has not been ranked one in the world since July 2011 but has produced a stunning run since returning from a long lay-off in February.
Fognini, ranked 19, nearly put a spanner in the works though before Nadal earned a 2-6 6-4 6-1 victory to reach the semis. “It’s (the number one ranking) something that doesn’t create more pressure for me,” Nadal, who will face fourth seed Tomas Berdych in the last four, said.
Fognini was a point away from taking a 5-1 lead in the second set and an upset was well on the cards but Nadal found his form in the nick of time.
Meanwhile, in the women’s event, Serena Williams brushed aside Dane Caroline Wozniacki 6-1 6-4 to advance to the semi-finals. She will meet third seed Agnieszka Radwanska.