The 22-year-old former US Open and French Open champion, who crashed in her opener at the All England Club 12 months ago, arrived under pressure to improve her modest grasscourt record and appeared to be in cruise control early on against Liu.
She eased through the opening set with minimum fuss and was on course for a routine victory when world number 146 Liu sprang to life and saved three match points in the second set, before forcing a tiebreak as the evening shadows engulfed Court One.
"I think I'm not playing my best tennis," Gauff admitted in her on-court interview, though she said there were positives.
"I think today I served well as I did in my last match, I held when I needed to. I definitely feel more confident."
Gauff's passive approach in the tiebreak allowed qualifier Liu to take control and level the contest at one set apiece, but she quickly regained her rhythm in the decider and broke in the opening game by forcing an error with a deep backhand.
Gauff glad missed chances did not derail her
"Yeah, I'm just happy to get through," Gauff added.
"I had some opportunities to close it out in the second set, but I'm glad I didn't let that derail me and was able to come out with a win today.
"I felt better today. I think Claire stepped up her level and I definitely had my opportunities with some of those match points, but it's only experiences that you can learn from."
The double major champion's serve came under pressure from Liu in the games that followed, but there was no looking back when she built a 5-2 lead, as she earned a fourth-round clash with Swiss 11th seed Belinda Bencic.
"The opponents I've played have been high level players and good grasscourt players. Belinda will be the same," she said.
"It'll be a tough one."
Wimbledon 2026
Wimbledon is taking place from June 29th to July 12th at the All England Club in south-west London. With 128 players in the draw, it is the third of the four Grand Slams of the tennis season and the only one played on grass.
Men's singles draw and results | Women's singles draw and results | All you need to know about the tournament | Find all our Wimbledon coverage here
