Simona Halep and Petra Kvitova have become the highest-profile casualties at this year’s US Open after they both lost in the second round on Thursday.

Wimbledon champion Halep, who was seeded at number four for the final Grand Slam of the year, looked well-placed to see off her American opponent Taylor Townsend after taking the first set in routine fashion.

However, 23-year-old Townsend, who had never previously made it through to the third round at Flushing Meadows, battled back to win the second before saving match-point during the decider and taking the victory via a tie-break.

The world number 116 will now face another Romanian, Sorana Cirstea, in the last 32 and she was clearly delighted to take the scalp of such a high-profile player like Halep. “This means a lot. It’s been a long journey.

I had a match point against Kiki Bertens at Wimbledon and close matches this year and not managed to get over the hump,” Townsend said. “This match gives me so much confidence that I can do it. When I’ve played Halep before I tried to make balls and played not to lose. Today I played to win.”

Halep was not the only big name to exit at the second round stage on Thursday, as sixth seed Kvitova was also dumped out of the competition, losing 6-4 6-4 to world number 88 Andrea Petkovic.

The two-time Wimbledon champion had been struggling with a forearm injury coming into the match and she was never able to get up to full speed, being broken three times by her German opponent, who will now face 25th seed Elise Mertens in the third round.

The defeats for Halep and Kvitova have once again thrown the ladies’ singles wide open in New York, with six-time winner Serena Williams currently leading the way at 3.75 to go on and win the tournament.