The last set became a lop-sided affair for Tianjin, which went on a 12-4 run to pull away and kept the advantage until the end.
Dilana took center stage early on by scoring seven points in a row, while Yang Shuyu provided much-needed help beyond the arc. The duo combined for 17 points in the first quarter to propel Dongguan to a 22-13 advantage.
"I've had two fantastic years here at Sydney FC and have cherished every moment of my life in Australia," he said.
During the 18-round campaign, teams face lung-busting altitude, scorching tropical heat, long-haul flights between many cities and passionate fans that make stadiums such as Argentina's La Bombonera or Brazil's Maracana among the world's most inhospitable venues for opponents.
Sichuan was held to six of 26 on three-pointers and out-rebounded its opponents 44-30.
Shaanxi's backcourt duo of Chen Yanyu and Chen Xinlei, who combined for 57 points in their last game, were restrained to nine and three points respectively.
The 40th edition of the London Marathon was rescheduled from its traditional April date due to the COVID-19 pandemic and was only eligible for elite runners over 19 laps around St James's Park. Enditem
"It's funny. Both of us had a tough week in Hambug, tough final. Then both of us was down in the first round with two sets to love. Both of us come back. Now we are here and we're going to play each other in quarters. It's like a nice press story of the match," Rublev said about his quarterfinals match against Tsitsipas.
The 30-year-old, who has been capped once for Argentina's national team, has struggled for opportunities since joining Boca from Mexico's Cruz Azul in January 2019.
Also on Saturday, fifth-seeded Stefanos Tsitsipas earned a spot in the fourth round after his Slovenian opponent Aljaz Bedene retired from the match and hobbled off the court when trailed by 6-1, 6-2, 3-1.
Ospina is the fourth player to be cut for the fixtures because of injuries or coronavirus restrictions, joining Porto pair Matheus Uribe and Luis Diaz as well as Leon midfielder Yairo Moreno.