Fernando Verdasco has booked his place in the semi-finals of the Barcelona Open after his opponent Kei Nishikori was forced to retire through injury.
World number 17 Verdasco had established a 4-2 advantage in the first set before Nishikori had to stop with the recurrence of a back problem.
The Spaniard will now face defending champion and fellow countryman Rafael Nadal for a place in the final.
The other semi-final is between Milos Raonic and David Ferrer.
