Poland's five-time grand slam champion faced a potential banana skin in her fourth-round encounter with the 128th-ranked German on Monday night, but handled the assignment with ease.
It took Swiatek just 59 minutes to complete the 6-0 6-1 rout at Rod Laver Arena.
Swiatek, who could reclaim the world No.1 ranking if she is crowned champion at Melbourne Park for the first time, next faces either eighth seed Emma Navarro or ninth seed Daria Kasatkina in the last eight.
The 23-year-old Swiatek gave up just five points on serve in a 24-minute first set and blasted a total of 27 winners in a dominant display.
She is yet to drop a set this Open campaign and feels her best is yet to come.
Lucky loser Lys had no answers to Swiatek, going down in less than an hour. (James Ross/AAP PHOTOS)
"There's a lot to improve, always. I don't feel like I'm in my peak yet," Swiatek said.
"For sure matches like that give me confidence and I feel like I'm playing a good game.
"I usually didn't feel comfortable (at the) Australian Open with my game but this year it's a bit better.
"I'm just enjoying being on the court and off the court as well, because for sure I have amazing time here and hopefully it's going to last even longer."
Swiatek is one win away from matching her career-best Open result, having lost to Danielle Collins in the semi-finals in 2022.
American Collins went on to lose that year's final to local favourite Ash Barty.
Lys, who was beaten by local Destanee Aiava in qualifying, was the first women's singles lucky loser to reach the Open's fourth round since the event moved to Melbourne Park in 1988.
The 23-year-old could have become the first woman in the open era to reach the quarter-finals at any grand slam as a lucky loser.
Despite her loss, Lys is set to rocket into the world's top 100 for the first time on the back of her first appearance in the fourth round of a grand slam.
Lys reached a previous career-high 105 in the world last September.
