Elena Baltacha believes a lack of aggression cost her as she lost to former champion Svetlana Kuznetsova in the second round of the US Open.
The British No.1 had made a brilliant start, winning the first three games - only for 15th seed Kuznetsova to raise her game and secure a 6-4 6-3 victory at Flushing Meadows.
And the 28-year-old Baltacha said: "I started really well and then she got on her game and it was hard. She had so much shape on the ball, far more than what I thought, and it drew me back. And she moved unbelievably.
"She had a very good match today, and I did the best that I could. If I could go out and play her again, would I do anything different? Yes, I would. I think I'd be more aggressive and I'd make more of an effort to push myself back onto the baseline."
Baltacha, the world No.58, was left unhappy with a number of calls during the match and she also felt hard done by on the final shot, so much so she refused to shake umpire Arnaud Gabas' hand.
Baltacha said: "I don't want to make an excuse because it's always the same for both but I thought that was on the line. I could be completely wrong but I got the feeling I got a little bit done there. But she was winning.
"I wasn't too happy. I think there were a couple. It was the heat of the moment. I'm sure he's had that before. He's a big boy, he can take it."
Baltacha, who has now reached the second round at five successive grand slams, will now take a couple of weeks off before heading to the ITF tournament in Shrewsbury and the WTA Tour events in Austria and Luxembourg.
Baltacha said: "I'm very happy with how I've played, I've had a great season.
"If someone had said to me at the beginning of the year I was going to finish (ranked) in the 50s, with everything I achieved last year, I would have said that would be a really good year, even better than last year I would say, the fact that I've managed to defend the points."