In addition, the quality of the 10 member teams means there are no easy games for anyone; the region boasts four national sides in FIFA's current top 10 and seven in the top 25.
"I can't get to sleep last night because I was so excited," The 43-year-old swimming fanatic said. "And I was not the only one - every one of our online group was awake late at night, cheering each other up for today's event."
"She played unbelievable today and she was everywhere and she hit all the balls in a very strong, very powerful way," the world No.2 said after the match. "It was a little bit cold and I couldn't be at my best."
The 19-year-old will face another qualifier -- Nadia Podoroska of Argentina in the semifinals. The latter stunned third-seeded Elina Svitolina 6-2, 6-4 to advance. Enditem
Esteghlal had been linked with former Werder Bremen coach Alexander Nouri but they failed to reach an agreement with the German-Iranian coach due to financial disagreements.
"It's because I did a lot of things well. I played more aggressively than the previous days. I went to the net more often, and I hit a lot of winners," added the 12-time French Open champion, who needed only one hour and 35 minutes to see off his opponent.
"We contained their three-pointer shooting quite well," Dongguan coach Lin Yaosen reflected.
Shandong built a 17-7 lead at the beginning of the second set, while Tianjin found it difficult to erase the deficit.
She lapped in under 45 seconds on a 1,100-meter-long indoor driveway and overtook other competitors before the end. And it cost her 50 yuan (about 7.36 U.S. dollars) for the six-minute drive.
Zhao Xuetong nailed 19 points for Sichuan. Gao Song and Hu Yueming each scored 17 points. Shao had 11.
Earlier on the Court Philippe-Chatrier, men's singles third seed, Dominic Thiem claimed another straight-set victory over 28th seed Casper Ruud, beating the Norwegian 6-4, 6-3, 6-1 to set up a last-16 clash against the winner between 2015 champion Stan Wawrinka and Hugo Gaston.