Starting the day ahead by one stroke, Li was five-under for the day and 20-under for the tournament. He was nearly further ahead but for a bogey on the 18th.
"It's actually a lot [more] comfortable than I thought. Quite surprised," Li said. "It's just another perfect day for me."
Li completed the par-five sixth at Golfclub München Eichenried in three shots on Friday and Saturday, but Sunday was the pick of the bunch as he hit a 21-yard chip into the hole. "Somehow it managed to go in," he said.
Li has two wins on the European Tour, at the 2016 China Open and the 2018 Dubai Desert Classic. The latter win, when he beat Rory McIlroy by one stroke, made him the first Chinese player to be ranked in the men's top 50.
Thomas Pieters moved into second with a six-under 66 including an eagle and three birdies on the back nine. "I just look forward to a really lovely day tomorrow and hopefully a lot of birdies," he said.
Jordan Smith is one shot further back at 16-under in third place, while Darius van Driel and Fox are another stroke back after van Driel managed the joint-best score of the day with an eight-under 64.
Ko's rocky round
Ko had a similarly inconsistent round to Fox. At the PGA Championship, Ko started the day in second but slipped back to 12th at one-under with a four-over 76.
She will start the final day seven shots back from leader In Gee Chun who shot 75 but still sits three clear of the chasing back at eight-under.
Ko had four bogeys over the opening seven holes but then recovered to get back to even-par through 14 holes when she bounced back with four birdies.
However she ended the round with bogeys on the final four holes to fall from what would have been a share of second.
Chun was holding her own until she made a double bogey on the par-five 16th hole. The two-time major champion from South Korea led by five shots after the first round and six at the halfway point, but that 36-hole advantage has been cut.
Lexi Thompson and Hye-Jin Choi both shot 70 and are tied for second with Sei Young Kim (71) at five-under par.
Alker still a chance for second major
At the US Senior Open in Saucon Valley, Pennsylvania, Alker will start the final round in a share of fifth, eight shots back from leader Padraig Harrington.
Alker had a horrid start to his third round with a double bogey at the second hole before dropping a further shot at the par four fifth. A welcomed birdie at the eighth was followed by back-to-back bogeys at 10 and 11 as it looked Alker's tournament was slipping away.
He found his form that has resulted in three victories already in 2022 and rolled in four straight birdies to finish with an even round 71.
"I had to kind of get something back, try and get back to at least under par," Alker said.
"But I just started committing a bit more to my shots. Just trying to get back into it and stay somewhere in there. It was kind of like I just freed it up and let it go.
"I was just making silly mistakes. That the difference."
Alker will need Harrington, who leads by five shots, to come back to the pack in the final round, and predicts he'll need a special round to have a chance for his second major.
"The course is starting to dry out a little bit. It depends on the pins. I'm not sure what's in his head right now.
"I'd have to go very low."
- With AP
