Kostyuk was one of the leading players on clay courts, winning two titles in a row before reaching the semi-finals of the French Open.
The 24-year-old did not play in the tournament ahead of Wimbledon, but returned home to Ukraine and spent his holiday in Greece.
While she said she was optimistic about transferring her clay form to grass, she had also not won on the surface for two years leading up to this year’s championships.
“I feel like for many years that I played here, I played terrible,” Kostyuk said.
“I couldn’t find my tennis on this surface, not at any tournament. It was a really difficult relationship for me.”
Kostyuk was still unconvinced when she arrived in London almost three weeks ago.
Losing in training sets to 44-year-old Serena Williams and Jessica Pegula did not give her confidence, contrary to the words of coach Sandra Zanevskaya.
“I turned to Sandra and said, ‘Can you tell me honestly right now whether you think grass is suitable for my game?’ She said: “100%,” Kostyuk said.
“It gave me something to hold on to.”