Muchova sends former champion Osaka packing in US Open second round

New York: Czech Karolina Muchova delivered a flawless display of serve-and-volley tennis to knock twice champion Naomi Osaka out of the US Open with a 6-3 7-6(5) second-round victory on Thursday.

Muchova enjoyed the best season of her career last year before a wrist injury sidelined her for 10 months, but she looked back to her best at Arthur Ashe Stadium as she set up a third round meeting with unseeded Russian Anastasia Potapova.

Four-times major winner Osaka of Japan, who missed last year's tournament while on a maternity break, was brilliant in her opening round win over 10th seed Jelena Ostapenko but a handful of costly mistakes sunk her chances against Muchova.

The two big servers were deadlocked early in the match before Muchova converted a break point when she forced Osaka into a backhand error in the seventh game, and the former world number one dropped serve again in the ninth.

Osaka broke Muchova with a powerful forehand into the corner in the ninth game of the second set and had the momentum as she went up 40-0 in the 10th.

But she let the match slip through her fingers as her forehand began to malfunction and the former world number one threw her racquet in disgust as she sent one long on the second break point, before Muchova battled through in the tiebreak.