Williams will take on Bulgaria's Tsvetana Pironkova, who overcame Alize Cornet of France 6-4, 6-7 (5), 6-3 in another round of 16 match.
Spain responded with a big chance at the other end of the pitch as a misplaced return pass from Emre Can to goalkeeper Kevin Trapp allowed Rodrigo Moreno to intercept the loose ball. However, Trapp denied Moreno after blocking the shot in the nick of time in the 14th minute.
Luis Enrique's team left it late and flabbergasted the hosts when Moreno flicked on a cross before Gaya poked home with a turn shot from very close range in the closing seconds of injury-time.
In the women's singles, fourth seed Naomi Osaka of Japan finished a routine job as she eased past Anett Kontaveit from Estonia 6-3, 6-4 to reach the quarterfinals.
To coach in Germany's top three leagues, one must obtain a football coaching licence, and the country has a strict and selective education system, he explained: "Each year, only 24 or 25 applicants are accepted at the only education venue, the Hennes-Weisweiler Academy in Cologne."
The RESTART of the ITTF will feature three of the most prestigious events, including the 2020 ITTF Women's World Cup, the 2020 ITTF Men's World Cup and the 2020 ITTF Finals.
In another third round clash, Australian Open champion Kenin had to weather a barrage of 35 winners coming from Jabeur's racquet, and stayed solid to break the Tunisian's serve three times, fighting her way to a 7-6 (4), 6-3 victory.
Moreno remained in the thick of things and kept Germany's defense busy as the striker hit an effort on target from a promising position in the dying seconds of the first half.
The last minutes of the first half witnessed the prowess of Saba. The Israeli striker added an open goal in the 39th minute, then delivered a precise cross for Ye Chugui six minutes later, helping the Guangzhou side lead 3-1.
Though the visiting Lithuanian team had two good chances on goal in the first half, the score remained 0-0.
Former Citizens star Sane against Spain indicated he is determined to not only take up competition at his new club in Munich but make his contribution to the German team.