Glasgow: An "upset" P V Sindhu rued that a historic gold medal at the World Badminton Championships slipped through her hands in the dying moments of the thrilling final against Nozomi Okuhara of Japan.

Sindhu and Okuhara fought tooth and nail in the gripping summit clash, described by many as the best women's singles final in recent times. The Japanese won 21-19 20-22 22-20.

"I am upset. In the third game, it was anybody's game at 20-all. Everybody aims for gold and I was there very close but that last moment changed everything," she said referring to crucial unforced error at 20-20 in the deciding game.

"She (Okuhara) is not an easy player. Every time we have played it is not easy, it is tough, tough rallies. I never took her easy. We never left any shuttle. I was prepared for a long match but I guess it was not my day," the 22-year old gritty Indian shuttler added.

Talking about the final, which was the longest match of the tournament, lasting one hour and 49 minutes, Sindhu said, "It was mentally and physically very tough".

"Each rally was long and we both were fired up and we both were fighting hard and it was so close, we were going like 14-14 18-18 and after 20-20 it is anybody's game. It was a big match, a good match but unfortunately I couldn't win."

Sindhu said overall the world championship final has been very satisfying for the Indians.

"We Indians are very proud that we won two medals with Saina also doing well. I am proud that I could win a silver for the country. It has given me a lot of confidence and I would come back to win more titles in future."

The Indian, who now has won three World Championship medals, said there was no need to tinker with the format and scoring pattern of the sport.

"I think 21 points is good, there will be long rallies and it won't be possible to keep it within 30-40 minutes because it a World Championship and everybody is a world class player," she said.

Okuhara had lost to Sindhu in the semi-finals of the Olympic Games last year in Rio de Janeiro and the Japanese said she had learnt a lot from that match.

"I learned a lot from that match. Today, I changed my strategy and tried to keep her moving more," she said.

"The third game was so close and I was absolutely exhausted. But I decided to try and enjoy it and I could see that she was very tired and was struggling. My attitude got me through," said Okuhara who became the first Japanese player to win a gold in singles in a World Championships.