"As players, we understand that we must maintain our discipline and professionalism at all times," said Hariss Harun, captain of the club which fields the national side's under-23 team.
"We apologise to our fans, coaches and technical staff for the incident. We know that such behaviour was unacceptable and we are regretful of our actions."
Singapore's Football Association has launched a probe after the match at the City State's Jalan Besar Stadium on Tuesday was called off 10 minutes before the end with the score locked at 1-1.
Young Lions players Gabriel Quak and Faritz Abdul Hameed were taken to hospital for checks after the fracas.
The Singapore FA said on Thursday it had given both teams until September 14 to file reports on the incident.
Young Lions team manager Eugene Loo said his club was conducting its own investigation.
"Such incidents are unacceptable and the players are very remorseful for their actions," he said.
"We apologise for the incident and we maintain that the discipline of our players will always remain a top priority. An investigation is currently ongoing and we will cooperate with the Disciplinary Committee to ensure that appropriate action is taken."
Young Lions lie seventh in the 12-team league, two spots above the Chinese side, with the season drawing to a close.
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