Chen Long celebrates with coach Li Yongbo after winning his quarterfinal match last week. [Photo/Agencies]

China's failure to defend three of its badminton titles at the Rio Games was a shock for a nation accustomed to dominating the Olympic courts, but head coach Li Yongbo called for calm amid the storm of criticism.

Four years after winning all five titles at the London Games, China grabbed two golds and a bronze to top the Rio medals table, but it was the nation's lowest haul at an Olympics for 20 years.

With teams restricted to two entrants in the singles, down from three in London, the badminton superpower had fewer chances to win medals.

However, the absence of a Chinese woman on the podium for both the singles and doubles was a major setback.

Li has been the face of Chinese badminton for more than a decade and survived a number of controversies by delivering unprecedented results at global and Olympic tournaments.

But the 53-year-old has been lambasted online over the team's performance in Rio, with calls for his resignation.

China will lose at least two of its gold medalists to retirement, with doubles veteran Fu Haifeng and two-time singles champ Lin Dan playing their last Games.

Zhao Yunlei, who won mixed doubles gold in London and took bronze in Rio, is also tipped to quit before the 2020 Games in Tokyo.

Li said China had little to fear about the passing of the golden generation, but conceded there will be more challenges as rival nations close the gap.

"Sometimes you're strong, sometimes you fall back," he said.

"Indonesia was once strong and Denmark, too. China has risen up, but the champions eventually retire and the next generation comes up slowly. So there will be some difficulties. This is normal.

"But China will still have top players competing in future because we have a lot of juniors at high levels.

"After these Games, our next generation will be strong. For a country to maintain its excellence it definitely needs to emphasize systemic talent development and very good training systems. China has, so I am not worried about the future."

Indonesia, Spain and Japan won the other titles in Rio.

"Badminton is developing on all sides," Li said. "But there is no point judging everyone else's progress, it's a matter of concentrating on your own.

"It is fair to say we have more difficulties than before, but that does not mean we are going to fall behind."