The ugly side of sports reared its head at China's National Games and tarnished the emerging appeal of rugby sevens in the country, experts said.

In protest of the refereeing at the final against Shandong, the Beijing female rugby sevens squad threw the match in the second half, standing still on the field while surrendering its end zone to their opponent, who won by an embarrassing 71-0 on Tuesday.

The Jiangsu team's Australian coach, Adam McDonald, even got physical with Beijing coach Jiang Xuming after blaming him for inciting his players to give up.

Experts blame the gold-obsessed sports system in China.

"It seems the match was thrown because of bad referee calls or injuries, but the farces at the games were a result of the sports system's obsession with medaling," said sports sociologist Lu Yuanzhen at South China Normal University.

The scene on the field sparked jeers from disgruntled crowds at the Shenyang Agricultural University Stadium and was reminiscent of the Chinese women's badminton doubles scandal at last year's Olympics. The pair were expelled from the Games after intentionally losing a group match for a preferable position in the knockout stage.

Although rugby team leader Zheng Hongjun claimed Beijing was a victim of Shandong's defensive fouls that referees didn't call, the public and media didn't buy it, slamming the team's lack of sportsmanship.

"Controversial calls are part of sports, especially contact sports. Complaints will happen, but quitting the match is unacceptable and should be punished," Xu Jiren, director of Xinhua News Agency's sports department, said on his micro blog.

Zhang Bin, a sports commentator on China Central Television, said the incident harms the game's public image, which was just gaining interest in the country after China got into the Olympic program.

"No one wins in a match like this," Zhang said.

Driven by elite results at the National Games, scandals including doping, age-cheating and match-throwing consistently happen at the quadrennial event.

At the 10th National Games in 2005, Liaoning's Olympic champion judoka Sun Fuming deliberately threw the +78kg final against Yan Sirui, who was from Liaoning but represented the People's Liberation Army delegation, so Liaoning and PLA could share the title, and the gold medals.

These cases cast a dark shadow on the image of the National Games, as well as Chinese sports, experts said.

According to a web poll on sina.com, more than 44 percent of the participants (more than 71,000 voters) agreed that "no matter how the referees performed, Beijing shouldn't have thrown the match".

In response to team Beijing's appeal for several controversial calls, the arbitration committee of the event stressed the referees' officiating was "fair and accurate" and disqualified Beijing's candidacy for the tournament's ethics award.

The Beijing delegation released a formal letter of apology for the team on Tuesday evening.

"We regret the women's team's reckless misconduct and officially apologize to those who love the sport and support us," the letter said.

"Their behavior failed to meet the public's expectations and has tarnished the images of both the sport and the National Games. We will conduct profound self-examination. Employees responsible for the incident will be seriously punished."

According to senior football promoter He Zheng, the Beijing team couldn't afford to lose the final because it was the favorite.

"Boasting the strongest lineups on the men's as well as women's teams at the National Games, the Beijing Sports Bureau set lofty goals and all the pressure fell on the women's team after the men unexpectedly lost at the semifinals," He said.