Elena Rybakina said her packed schedule in the wake of last month's Wimbledon victory had left her with little time to prepare for the hardcourt season after she made a first-round exit from the Silicon Valley Classic in San Jose on Monday.
Rybakina, playing her first match since her win over Ons Jabeur in the final of the grasscourt major, lost 1-6 6-2 6-0 to Daria Kasatkina. Seventh seed Rybakina looked to be in control early on but lost 12 of the last 14 games of the match.
"I was playing well in the first set and then conditions changed a bit and I think physically, I completely lost focus in the end," Rybakina said.
"Of course it was a tough week after Wimbledon. I had many things to do, I had a lot of travelling. I didn't have enough time to prepare for the hard season.
"I just wanted to come here and try my best because I knew I was coming to a very tough tournament. Here there are so many great players and I knew I could play in the first round with someone in the top 10."
