Elsewhere, Eintracht Frankfurt came from behind to beat Hoffenheim 2-1. Borussia Monchengladbach wrapped its first victory of the campaign after easing 3-1 past rival Cologne. Wasteful Bayer Leverkusen shared the spoils with newly-promoted Stuttgart following a 1-1 draw and Leonardo Bittencourt's sole goal of the match helped Werder Bremen to edge newcomer Armenia Bielefeld. Enditem
"We mainly worked on guarding their three-pointers, also doing well on 3-pointers and rebounds on our own," Dongguan coach Lin Yaosen commented.
Dongguan established a 22-12 advantage after the first quarter, with Dilana scoring 10 points to lead the way.
Dilana Dilishati finished with a game-high 21 points. Zhang Dongxia registered a double-double of 10 points and 12 rebounds.
It was also the 96th victory at Roland Garros for the Spaniard, who is seeking a 20th Grand Slam title to equal Roger Federer's record.
Reims took an early lead through captain Yunis Abdelhamid's header in the 11th minute. But goals from Raphinha and Damien Da Silva put Rennes in front at the break.
The second set was filled with breaks as both players failed to hold their serves from the 6th to the 11th game. Zhang served to win in the 10th game but was broken by her French opponent. However, when the chance appeared again in the 12th, Zhang didn't miss it and wrapped up the victory with a flawless love game.
With five players on target, Atalanta enjoyed another convincing victory as the Dea crashed Cagliari 5-2.
"It was a very even match, perhaps more difficult than the result showed," said Djokovic, who is seeking for an 18th Grand Slam title.
"I think I played a really good match. I was very aggressive. I knew from last year I had to change something, so I really wanted to be better than last year and definitely, I was today," said the world No. 2.
"It's been long ride definitely. Everything came to my mind when I had my whole family, people who I loved to help me through the tough, tough time," said Kvitova. "I was just playing in the Philippe Chatrier, it was such nice to win the match and to be in the quarterfinal."