LONDON (Reuters) - The London Games badminton tournament was rocked by the biggest scandal to hit the sport in its 20-year Olympic history, casting a pall over China's stunning sweep of the five titles on offer.
The sport's federation sowed the seeds of the scandal by introducing a much-criticised format of round-robin matches in a pool-based first round, which left the tournament ripe for manipulation by teams seeking to secure preferable positions in the knockout rounds.
Organisers brushed off warnings from team officials and the competition was plunged into turmoil on day four when four women's doubles pairs deliberately played to lose their matches in farcical scenes at Wembley Arena.
China's world champion pair of Yu Yang and Wang Xiaoli were blamed for kicking off the match-throwing antics against South Korean opponents, but both pairs were culpable as they blatantly sprayed shots out and hit serves into the net, sparking jeers from a disgruntled crowd.
Despite repeated warnings from tournament referees, the shenanigans continued in a later match between South Korean and Indonesian opponents.
"Who would want to sit through something like that?" London organising committee chairman Sebastian Coe asked. "It is unacceptable."
Within hours, all eight players had been charged with misconduct and they were subsequently expelled from the tournament in a stunning decision that polarised teams and officials.
South Korea and Indonesia appealed against the expulsions but China's delegation backed them and ordered head badminton coach Li Yongbo and the players to issue a public apology.
Indonesia subsequently withdrew its appeal.
The scandal rumbled on, with the IOC demanding the affected delegations investigate their coaches' involvement in the negative tactics, overshadowing fiercely contested matches played out in front of near-packed houses every day.
China's peerless badminton team shrugged off the furore, saying it would motivate them to an unprecedented sweep of all titles and they duly backed up their fighting words.
After Yu and Wang were expelled from the Games and booted out of the athletes' village, China's second-ranked women's doubles pair of Zhao Yunlei and Tian Qing stepped up to win the gold by thrashing Japan's Mizuki Fujii and Reika Kakiiwa.
That made Zhao, a round-faced, 25-year-old from a bustling Yangtze river port, the first to win badminton golds in two events at the same Games, having already won the all-China mixed doubles final with partner Zhang Nan.
Malaysia's Lee Chong Wei set up a shot at redemption and re-match with reigning champion Lin Dan to make the final of the men's singles, four years after losing the gold-medal decider to the Chinese at Beijing.
Lin prevailed in a three-game classic to become the first male player to defend a singles title, underlining his claim as the finest badminton player of all time.
Lee, who held the number one ranking for much of his career but never won an Olympic, world or Asian Games title, was crushed after coming within two points of gold in his final Games.
China hailed a bright new talent in 21-year-old Li Xuerui, who mowed through a succession of opponents before upsetting top-seeded compatriot Wang Yihan for the women's singles title.
China's veteran pair of Cai Yun and Fu Haifeng completed the sweep by capturing a long-awaited men's doubles gold after being denied on their home court in Beijing.
They blitzed Danes Mathias Boe and Carsten Mogensen in the final, but Denmark were thrilled to defy Asia's badminton powers by poaching a silver and a mixed doubles bronze.
India celebrated a maiden badminton medal with a fortuitous bronze in the women's singles to Saina Nehwal after her Chinese opponent retired hurt.
Indonesia, though, were plunged into gloom when their proud record of producing an Olympic champion at every tournament ended with a thud, the team failing to take a single medal.
Russia snatched an unlikely bronze in the women's doubles after the already-eliminated Nina Vislova and Valeria Sorokina were re-instated in the draw following the expulsions.
Questions about the tournament's credibility are likely to continue, with the heat still on world badminton to probe the role of the coaches behind the disqualified players.
(Editing by Clare Fallon)