Heather Watson was shocked by her poor performance against Sorana Cirstea in the first round of the US Open.
Nothing went right for the British number one, who won just 12 per cent of second serve points in a 6-1 6-1 loss that lasted 54 minutes.
Watson said: "The first few games I was okay and then as soon I got broken in that first set she stayed playing well the whole rest of the match and I didn't play very well.
"I made a lot of errors, a lot of double faults. It was partly because she was hitting some good shots, so maybe I tried to go for a winner too soon.
"It was just over very quickly. She hasn't been in great form and I've been having a good year so I didn't expect to play like this, I didn't prepare to play like this. I thought I was playing pretty well in practice."
Watson has had an excellent season, climbing from a low of 161 in the rankings at the start of February to 46 and posting her first two wins over top-20 players.
Cirstea, on the other hand, has slumped from 21 a year ago to 80 now and this looked a good first-round draw for Watson, but the Romanian began the match showing form of old, thumping aces and forehands and leaving Watson reeling.
It did not help that the British player, who has developed her own attacking game to great effect this season, was struggling to find her first serve.
"It was an opportunity on paper but she still played very well today and I give her a lot of credit," said Watson.
"Also she served well, hit quite a few aces, and me not so much. I couldn't find my serve. I'm not quite sure why but I've got to look back and try to improve on that."
From 1-1, Watson lost six games in a row and, although she seemed to get a foothold with a break of the Cirstea serve in the second game of the second set, it was a false dawn.
Watson had beaten Cirstea in their three previous meetings, most recently in Fed Cup earlier this year, and in 2012 in Miami she won from 5-0 down in the deciding set, but a comeback never looked on the cards this time and Cirstea took her first match point with another forehand winner.
Watson's exit leaves Andy Murray once again as the only British singles player left in the tournament.