Rafael Nadal battled through the pain barrier to beat fellow Spaniard Nicolas Almagro in 3 sets to reach the fourth round of the US tennis Open in New York.
Nadal, who was sidelined for with tendinitis in both knees during June and July, suffered another setback on a Arthur Ashe Stadium when he received treatment for what television commentators said was "a right abdominal muscle injury he first suffered in Cincinnati."
At 2-1 down in the third set, Nadal lay flat on his back as one of the tournament medics sprayed and taped his stomach.
After resuming play, the third seed grimaced on several occasions as he poked the afflicted area between points.
Despite the injury, Nadal hung on to beat his childhood friend Almagro, sealing the match with a scorching backhand to end an entertaining 15-shot rally.
Nadal, who needs the US Open title to complete his collection of grand slam titles, will face either French 13th seed Gael Monfils or Argentina's Jose Acasuso.