The 28-year-old opened the competition with a first round effort of 64.39 metres. She went on to improve her mark to 66.85m in the third round and bowed out with a 66.26m to wrap up the victory, reports Xinhua news agency.
Lyu improved the previous meet record of 64.08m set by herself in 2015 by a margin of 2.77 metres.
It was also her best performance of the current season, but was still shy from her Asian record of 67.59m registered when winning the silver at the World Championships in London last summer.
The 29-year-old Gong, the winner of the Diamond League trophy last year, beat a loaded field with five over-19m throws. Her winning mark came from the second round and in fact each of the five valid marks was good enough to seal the title for the local star.
"My plan was to break 20m today but unfortunately I was just one centimeter short of the mark," Gong said. "I probably will not join every Diamond League race this season, but I will try to get more points in each race I compete in."
Defending world indoor champion Anita Marton failed to compete to her best level and only settled for the sixth place at 18.16.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)