It is eight months since she suffered career-threatening injuries when she was stabbed in her playing hand by an intruder in her home, and was forced off the tour for five months.
The twice Wimbledon champion won through to the second round of the US Open by beating former world No.1 Jelena Jankovic of Serbia 7-5 7-5 on Monday.
"Things like seeing other players, seeing coaches, being on the tennis court, practising with other girls, that feels more normal than before, for sure," the 13th seed told reporters.
"For me, like, warmups before the matches or matches are already normal, I have to say.
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"But on the other hand, it's still very special and I'm still very grateful for it.
"Yeah, few things are more normal than before, but few are still a little bit different."
Kvitova, in search of top form after a mediocre build-up to the year's final grand slam, struggled to adapt to Jankovic's counter-punching style but eventually wore down the 2008 runner-up to set up a meeting with France's Alize Cornet.
"She did just a great job, mentally, because from what I heard it was not even sure that she could play tennis again," Cornet, a 6-4 6-4 winner over Britain's Heather Watson, said.
"I'm really happy for her because she is a very nice person and there are not so many of them on the tour."
Kvitova had nearly four hours of surgery on her left hand after the December attack and returned to competition at this year's French Open.
