As Emma Raducanu arrives in New York for the US Open, she is aware of how hard she will have to work physically to compete at the highest level.

But after beating two top-50 players, the 18-year-old retired with breathing difficulties and dizziness when trailing Ajla Tomljanovic 4-6 0-3.

"I think Wimbledon was an extremely positive experience," she said.

"I learnt so much just about my game, and what it takes to perform at the top. It's definitely shown me how much work I need to do physically."

Speaking after her first practice session in New York, Raducanu added: "I haven't done much work relative to these other girls who have been on tour for 10 years, and then to be playing the intensity I was at for a couple of weeks in a row, it was something completely new to me.

"I think that's definitely a big gap in my game, and since then I've just been working on trying to physically get stronger and have better endurance."

Raducanu has had a lot of success since Wimbledon. She was awarded an A* in Maths and an A in Economics on A-level results day.

She then reached the final of last week's WTA Challenger event in Chicago, and now stands at 150 in the world.

Her next challenge is to negotiate three rounds of qualifying for the US Open. Her first match will be against the experienced Dutch player Bibiane Schoofs in expected high heat and humidity on Wednesday.

"I played in some pretty challenging conditions in Landisville, Pennsylvania," Raducanu says of an event at which she reached the quarter-finals as a qualifier, before retiring with heat exhaustion.

"It was extremely humid and hot - the heat rule was in play most of the days there. So I think that after playing there for 10 days I've kind of acclimatised pretty well and I'm actually feeling in physically pretty good shape."

Raducanu has also changed coaches since Wimbledon, replacing the highly experienced Nigel Sears with the former British tour player Andrew Richardson.

"I really respect Nigel, and me and Nigel got on great. I think very very highly of him, but I think at this stage of my development a fresh voice, and fresh eyes are sometimes good," she continued.

"Nigel was extremely good especially at the top of the game and I think that's where he probably brings the most value.

"But I think right now for where I'm at - a nice development step is to get a few more voices in."