The former world No. 1 is to face a tougher challenge in the second round against 2017 champion Jelena Ostapenko of Latvia, who knocked out American Madison Brengle 6-2, 6-1.
Elsewhere, Borussia Monchengladbach are still waiting for their first win of the season as they shared the spoils with Union Berlin following a 1-1 draw.
Yan Yuxiang from Shandong took first place in the men's 200m butterfly in 2:00.18, with Tianjin's Wu Guangshuai and Hunan's Wang Kecheng rounding out the top three.
Attracting around 300 of China's top swimmers, the 2020 Championships are being held from September 26 to October 2 in Qingdao.
The win also saw the team from northwest France climb to the top of the table, two points clear of second-placed Lille.
"I think the time will be fast, London is a big race and all the participants are in good shape and able to run faster times," Kipchoge, who holds the official world marathon record of 2:01:39, told Xinhua on Sunday.
Zhang wants to improve her time further in 200m butterfly after the championships.
Serena Williams of the United States serves during the women's singles first round match against Kristie Ahn of the United States at French Open tennis tournament 2020 at Roland Garros in Paris, France, Sept. 28, 2020. (Xinhua/Gao Jing)
There was drama in the last minute of injury time when Robin le Normand had the ball in the Valencia net only for the VAR to rule it out for handball.
"(I'm) struggling to walk so that's a tell-tale sign that I should try to recover," she added.
While Barca's pre-season was all about veteran players leaving and Leo Messi wanting to leave the club, their league debut at home to Villarreal was all about Ansu Fati. The 18-year-old was at the heart of nearly all the good things his side did in the first half as they went 4-0 up in just 45 minutes to assure Ronald Koeman a placid debut as coach. He scored the first two goals with an exhibition of cool finishing and then provoked the penalty which Messi slotted away to make it 3-0.