Oscar, who cost SIPG a whopping €60 million (US$67 million, RM287 million) in the last transfer window to become the biggest transfer in Asian football history, sparked the confrontation when he deliberately lashed the ball twice at R&F players.
When the ball bounced back to him he smashed it again in the opposite direction - hitting the midriff of another Guangzhou player.
The home side's Chen Zhizhao retaliated, pushing the 25-year-old Brazilian to the ground.
Oscar fell to the ground after which a fight between the two teams broke out as the coaching staff, players as well as substitutes charged against each other in an aggressive fight that went on for a few minutes.
Nevertheless, Oscar's teammate Fu Huan saw red, as did Guangzhou's Li Tixiang.
Oscar was unhurt and the fiery encounter finished 1-1 to leave Villas-Boas' side four points behind reigning champions Guangzhou Evergrande.More news: 79 now believed to have died in London high-rise fire
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"Disrespect the opponent? It is not true", the Brazil worldwide is reported as telling the Sina news agency.
The Guangzhou players angered by Oscar's action surround the player before his Shanghai team-mates entered the fray as punches were thrown and both benches joined in the ugly scenes.
The club also released an official statement saying that they were sorry for what happened at the field.
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