Japanese ace and world No.1 Osaka is into the last 16 in the Nature Valley Classic in Birmingham.
But she was given a scare by Maria Sakkari of Greece before winning 6-1, 4-6, 6-3.
The tournament is Osaka’s only grass-court event before going to Wimbledon.
The 21-year-old Australian Open and US Open champion explained her frustrations, saying: “I should be able to adapt but it just takes longer than I want.
“I would rather it be at a quicker rate. The time that I get most comfortable is during Wimbledon, so there’s a repetition that needs to happen sooner for me as I would love to learn how to get more comfortable early.
“But it’s a surface that I think suits my game and I have a lot of potential to play well here, so hopefully one day it will click.”
Osaka’s world No.1 spot could be in danger this week if world No.2 and French Open champion Ashleigh Barty wins in Edgbaston.
But Osaka admitted she is trying to stop worrying about her ranking.
She added: “During my entire clay season, it kind of mattered and I think it showed because I was stressed out the entire time.
“Now I’m just having fun. I’m enjoying it and I know that if I play well, then I’ll be No. 1. But I’m not trying to keep that in my mind.”
Meanwhile, Maria Sharapova insists she is “hungry” to make more memories at Wimbledon after returning to action on grass.
The five-time Grand Slam champ won her first match since February at the Mallorca Open, saving two set points to see off Viktoria Kuzmova 7-6, 6-0.
The Russian who served a 15-month drugs ban from the 2016 Australian Open, struck 16 winners and converted five of her seven break points.
Sharapova, 32, who won at SW19 in 2004 aged 17, is now looking ahead to being back in the main draw at Wimbledon after a series of shoulder and arm injuries.
She reflected: “It always brings incredible memories.
“They’re memories I’ll hold for the rest of my life, and as the years go on, they become more valuable because you understand the triumph and what you achieved as a young girl.
“It was an incredible moment but I’d like to have the perspective where I go into a tournament hungry for more.
“It’s been a while since I’ve been out there, so it was good to put down a few things I’ve worked on, put the arms into action. There’s still a lot to work on and improve, but I had to start somewhere.
“In tennis, there’s always something around the corner but when you’re coming back from injury, it’s hard to think from that perspective. I want to perform well at big tournaments but I needed to start somewhere.
“I haven’t played much on grass in the last few years, so it’s about playing, working, improving a few things, and getting the rust off.”