Kvitova went into the match quickly as she broke her Chinese opponent twice to surge to a 4-0 lead in the opening set, before serving for the set in the eighth game.
"To be honest I was over the limit today. At the end I gave everything that I had out there, it was an amazing match," the 27-year-old added.
1: Barca still has work to do
Next up for Halep is another 19-year-old youngster, Iga Swiatek of Poland, whom Halep defeated in the round of 16 here last year.
On the Shandong side, Yang Hengyu contributed 16 points, while Qiao Yanzi added 12.
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.
"We are in a very strange situation, after a lot of months without much tennis, especially for me, that I didn't play in America, I don't know if it's a positive thing or a negative thing," Nadal said when asked how important it was to keep the early-round matches short and sweet.
FC Barcelona coach Ronald Koeman was left frustrated as the club failed to complete deals to bring central defender Alex Garcia and forward Memphis Depay to the club from Manchester City and Olympique Lyon respectively.
Dominic Calvert-Lewin's 16th minute header put Everton ahead only for Jordan Pickford's error to gift Neal Maupay a 41st minute equalizer.
In other games in Chengdu, after a goalless first half, Beijing Renhe broke the deadlock in the 57th minute to claim a 2-0 victory over Suzhou Dongwu. Taizhou Yuanda defeated Inner Mongolia Zhongyou 2-0.
Jiangsu played a more aggressive game in Tuesday's faceoff with Shanghai, which had led the championship group before the third round. In the 70th minute, Wu Chengshu received a pass from the left side and rifled an effort into the net, helping Jiangsu gain a 1-0 lead.