The win meant Qingdao continue to lead the overall standings, although second-placed Ruichang Biyuan also cruised to a victory, beating second from the bottom team Anhui Souyu 4-1 later in the day.
Williams defeated Russia's Margarita Gasparyan 6-2, 6-4 while Kenin needed an hour and 22 minutes to maneuver past Canadian youngster Leylah Fernandez 6-4, 6-3.
Spain now move top of Group A4, one point ahead of second-placed Ukraine. Germany are third on two points after they lost 1-0 to Switzerland.
Stephens went up a double break to carve out a 5-2 lead and served out the opening set in just 38 minutes. But Williams began to raise her game and served much better in the second set, lifting her first-serve percentage from 50 to 76 percent. By breaking twice, Williams won the second set to level the match.
"After removing the two words, the emblem becomes simpler, which makes it more applicable on designs including apparel and licensed products," she added.
Elsewhere, Belarus' fifth seed Aryna Sabalenka lost to compatriot Victoria Azarenka 6-1, 6-3, ninth seed Johanna Konta of Britain was stunned by Romania's Sorana Cirstea 2-6, 7-6 (5), 6-4 and tenth seed Garbine Muguruza from Spain lost to Bulgaria's Tsvetana Pironkova 7-5, 6-3.
Peters, 26, who is riding in his maiden Tour de France, produced a brilliant long-range solo breakaway to record his first stage win, leading Toms Skujins and Carlos Verona, who arrived at the same time, by 47 seconds.
But it was another nightmare weekend for Ferrari on their home turf. Before Leclerc's accident, his teammate Vettel had become the first retirement of the race, pulling off with brake failure on lap six after having qualified a lowly 17th.
"I just don't know what to say, it was really close to a perfect moment," Vetter told World Athletics.
Despite the easy win, the Russian star said his opponent has a bright future.
After dropping his serve to trail 6-5 in the first set of his fourth round match against Spain's Pablo Carreno Busta, Djokovic angrily smashed a ball in frustration which struck the line judge in the neck, causing her to fall to the ground.