A closely fought opening game of the Group B match saw Sun overcome the Spaniard 21-18 and with the momentum on her side, looked on course to complete a straight games triumph by winning the second.

Marin would have other ideas as she saved eight consecutive match points to draw level in the game.

The two-time world champion expressed frustration on court at the conduct of her rival, with Sun receiving a warning from the umpire and then requesting a treatment for an injury.

The Chinese player would be back on her feet shortly afterwards and would eventually secure a 21-18, 24-22 victory.

She would be joined at the top of the group standings by Olympic silver medallist Pusarla Sindhu, who came from a game down to battle past Japan’s second seed Akane Yamaguchi, winning by a 12-21, 21-8, 21-15 score.

Group A of the women’s singles event saw world number one Tai Tzu Ying of Chinese Taipei secure a straightforward 21-16, 21-13 win over China's He Bingjao, while South Korea’s Sung Ji Hyun beat Thailand's Intanon Ratchanok 21-19, 21-11.

The men’s singles competition saw a surprise result with world number one Lee Chong Wei, the newly crowned BWF Men’s Player of the Year, falling to a straight games defeat.

Having last played in October, due to suffering from a hamstring injury, the Malaysian got off to a slow start and was punished by South Korea’s Son Wan Ho as the newly crowned Korea Open champion triumphed 21-10, 21-16.

Last year's runner-up Viktor Axelsen would also earn victory in Group B, with the Dane emerging as a 21-13, 21-17 winner against Hong Kong’s Ng Ka Long Angus.

His compatriot and tournament top seed Jan Ø Jorgensen produced arguably the most complete display of the first day of action, as he thrashed Hong Kong’s Hu Yun 21-8, 21-5 in Group A.

China’s Tian Houwei won the group’s second match of the day 21-15, 21-7 against Marc Zwiebler, who became the first German player to feature at the season ending tournament.

There was a surprise result in the mixed doubles competition, with Olympic champions Tontowi Ahmad and Liliyana Natsir losing 21-11, 21-12 to fellow Indonesians, Praveen Jordan and Debby Susanto.

Denmark’s Joachim Fischer Nielsen and Christinna Pedersen would also earn a victory in Group A, with the duo coming through to win 21-14, 21-23, 21-16 against South Korea's Ko Sung Hyun and Kim Ha Na.

Defending champions Chris and Gabby Adcock of England got off to a fine start by sealing a straightforward 21-15, 21-9 win against Japan's Kenta Kazuno and Ayane Kurihara in Group B, before China’s Zheng Siwei and Chen Qingchen beat their compatriots Lu Kai and Huang Yaqiong 21-18, 13-21, 21-14.

There was another all-Chinese clash in the men's doubles with Chai Biao and Hong Wei sealing a 21-18, 16-21, 21-15 win over last year's runners-up Li Junhui and Liu Yuchen in Group B.

Malaysia’s Goh V Shem and Tan Wee Kiong had been due to contest the second match in the group, but saw their opponents Carsten Mogensen and Mathias Boe of Denmark withdraw, with the latter suffering from illness.

However there was success for their fellow Danes Mads Conrad-Petersen and Mads Pieler Kolding, as they beat top seeds Takeshi Kamura and Keigo Sonoda of Japan 21-15, 21-17 in Group A.

Marcus Fer Gideon and Kevin Sanj Sukamuljo then won an all-Indonesian match 21-18, 17-21, 21-14 against Angga Pratama and Ricky Kara Suwardi.

Olympic women’s doubles champions Misaki Matsutomo and Ayaka Takahashi were forced to battle to a 21-19, 21-19 victory over their fellow Japanese pairing Naoko Fukuman and Kurumi Yonao.

They were joined at the summit of Group A by Chang Ye Na and Lee So Hee, after the South Koreans sealed a straight games 21-19, 21-15 win against defending women's doubles champions Luo Ying and Luo Yu of China.

There was no such problem for the second Chinese pairing Chen Qingchen and Jia Yifan, as they won 21-18, 21-12 against South Korea’s Jung Kyung Eun and Shin Seung Chan in Group B.

Olympic silver medallists Christinna Pedersen and Kamilla Rytter Juhl of Denmark would also earn a victory, overcoming Malaysia’s Vivian Hoo and Woon Khe Wei 21-7, 21-17.