"We inflicted great pressure on our opponents throughout the game. Offensively we played inside out and showed our level," Inner Mongolia coach Zheng Wei reflected.
He is also doubtful for Barca's next games, which are away to Getafe on October 17, their Champions League debut at home to Ferencvaros on October 20, and the first 'Clasico' of the season at home against Real Madrid five days later.
"We played a little tight at the start. We improved later in the match, and showed our character," said Zhejiang coach Gu Jiaqing.
Union gained momentum but missed the chance to extend the lead at the half-hour mark after Nico Schlotterbeck pulled wide from tight angle.
"I know footballers play under these conditions, but they are all the time moving," said Nadal after the latest ever finishing time for a match at the tournament.
"Despite its huge popularity in many countries, racquetball is still new to Chinese people. It is a high-speed sport that needs long-term practise and systematic training," said Liu.
The win, which came as the 35th from 36 matches this season, also ties him with Rafael Nadal for a record 14th Roland Garros quarterfinals appearance.
Universidad Catolica midfielder Jose Carabali also earned his first national call-up for the matches in Buenos Aires on October 8 and Quito five days later.
Also absent will be representatives from Oriente Petrolero, due to bickering between club officials and the Bolivian Football Federation (FBF).
Sunday's win and the midweek victory against Valladolid were largely thanks to goalkeeper Thibaut Courtois, who produced man of the match performances in both games to keep Madrid's rivals at bay.
Freiburg staged a well-positioned defense from the kickoff and was able to keep Lucien Favre's men on the distance in the opening stage.