The top seed Rafael Nadal has secured a place in the quarter-finals of the U.S. Tennis Open with a 6-2 5-7 7-6 6-3 win over Sam Querrey.
Nadal is chasing his first title in New York and made light work of the first set but found himself under pressure in the second and a string of unforced errors showed he is not invincible.
The 20-year-old American lost his own serve twice,but broke the world number one three times to take the set.
After taking the third, Nadal seemed back in charge in the fourth, winning a break in the sixth game.
But Querrey refused to give up, creating seven break points in the seventh game and forcing Nadal to dig deep to survive.
