NEW YORK, Sept 7 (Reuters) - Doubts over Elena Rybakina's fitness lingered until the eve of the U.S. Open and the Kazakh said she was amazed by her progress from an ankle injury after reaching the quarter-finals on Monday to edge closer to the world number one ranking.
The second seed arrived in New York without having played since retiring from her Cincinnati Open quarter-final against Iga Swiatek last month but has pieced together a superb run to storm into the last eight without dropping a set.
She took apart two-times winner Naomi Osaka in the fourth round to set up a meeting with Olympic champion Zheng Qinwen, and another victory will help her leapfrog Aryna Sabalenka and secure top spot in the rankings next week.
"My preparation wasn't that great. I didn't play for seven days and I couldn't do much in the gym movement-wise, so we had to really go day by day," Rybakina told reporters.
"It's amazing progress. I'm really glad how everything worked out. We didn't even know if I'm going to be able to play or not. I have a great team. Also, a good doctor on the phone all the time.
"I can't say that all the matches were amazing, but today it was one of the best matches I played."
Rybakina had never previously reached the quarter-finals of the U.S. Open and she said her latest run had improved her relationship with the tournament and New York.
"Well, now it's getting better and better," she added.
"I usually don't perform that well. Now I feel like this year it's the best for now out of all the years that I've played here.
"I like New York and it's an amazing city. For me, maybe just for two, three weeks, because afterwards it might be too much. I really love the crowd here.
"I enjoy playing in stadiums like this."
(Reporting by Shrivathsa Sridhar in New York; Editing by Peter Rutherford)
