World number one and defending US Open champion Rafael Nadal sent his close friend David Ferrer into Grand Slam retirement on Monday when his veteran compatriot was forced to quit their first round match with an injury.

David Ferrer, a former world number three but now standing at a lowly 148, called it quits on a hot and humid night on Arthur Ashe Stadium when he led 4-3 with a break in the second set. Top seed Nadal had taken the opener 6-3.