"In the end it got too dark to go for 6.15 meters and I felt it was unsafe to continue any further," said the world silver medalist. "I felt I was in the zone. But you have to be prudent."
The victory sends Garcia into the third round, equaling her best US Open result after finishing at that stage every year from 2016 to 2018.
With this result, Dalian are sixth in Group A with nine points, while Henan with six points remained in last place. Enditem
In women's singles, top seed Pliskova of the Czech Republic was upset by France's Caroline Garcia in the second round.
Fourth seed Naomi Osaka of Japan booked her place in the third round with a comfortable 6-1, 6-2 win over Italy's Camila Giorgi.
The 28-year-old is now 16th in the overall rankings, 16 seconds behind new leader Yates.
In other matches on Wednesday, Ceara beat local rivals Fortaleza 1-0, Atletico Goianiense drew 1-1 at Fluminense, Corinthians won 2-1 at Goias and Bragantino drew 1-1 at Athletico Paranaense. Enditem
World number one Djokovic struck 51 winners to notch up the win against Edmund, extending his unbeaten run this year to 25 matches.
The hosts added their third goal when Daniel Sampaio latched onto Marco Antonio's pass to slot home in stoppage time.
Duplantis tried to challenge Sergei Bubka's 26-year-old outdoor record of 6.14 meters, but failed to continue after one unsuccessful attempt at 6.15 meters as darkness set in.
"I was really focused each game and each point. Especially against top players, one point can make the difference. So I had to stay very calm and keep going," the world number 50 added.