Scotland: China`s Lin Dan came from behind to keep alive his hopes of a sixth world title on Wednesday as the 33-year-old saw off Denmark`s Emil Holst 19-21, 21-8, 21-16 in a draining 81 minutes.
The decider was close, with the score tied at 16-all before Dan`s greater experience helped him win the final five points and gain revenge for a defeat in the Danish Open earlier this year.
Seeded seventh, Lin Dan admitted he was relieved to get through to the last 16.
"I am very happy to win and prove myself again at the world championships," he said.
"I have prepared very well and for a long time for this week and although it was a long match I am now looking forward to tomorrow."
Holst, the world number 39, was heartbroken at missing out on a chance to claim the most famous of scalps.
"I am very disappointed," admitted the 26-year-old. "I had my chance to beat him, but I was very tired towards the end and he made me make tough decisions."
In the longest match of the championships, Vincent Wong Wing Ki, 12th seed from Hong Kong, survived a scare to overcome Japan`s Kanta Tsuneyama.
The Japanese underdog had three match points -- and had to save two of Wong`s -- before he went out 23-21, 15-21, 24-26 in a marathon one hour and 24 minutes.
"I wasn`t too nervous when I was facing the three match points because I already prepared myself for a long and tough match," said the winner, who sank to his knees in relief at the end.
"I lost to him recently in the Asian championships so I knew it would be difficult. I am the 12th seed so the pressure is on me."
Defending champion Chen Long and top seed, Son Won Ho, both had easy passages into the last 16.
Chen, the Olympic gold medallist and fifth seed, trounced Indonesia`s Sony Dwi Kuncoro 21-3, 21-9.
South Korea`s Son defeated Hungary`s Gergely Krausz 21-13, 21-9.
"I am so happy to have won in only two games," said Chen. "But I want to be prepared for the whole tournament. It will get harder."
There was a huge shock in the men`s doubles with top seeds Li Junhui and Liu Yuchen failing to get past their first match, losing to a relatively new Indonesian pairing of Mohammad Ahsan and Rian Agung Saputro.
It was three close games, but Ahsan and Saputro came from behind to win 19-21, 21-18, 21-18.
In another surprise, South Korea`s Chung Eui Seok and Kim Dukyoung knocked out Malaysian fifth seeds Goh V Shem and Tan Wee Kiong 21-18, 21-16.
In the women`s singles, second seed Sung Ji Hyun opened her title bid with a 21-9, 21-19 win over India`s Tanvi Lad.
Mia Blichfeldt scored the first upset when the Dane upset Japanese 10th seed Sayaka Sato 21-14, 14-21, 21-18.
Sato was the only seed to go out of the women`s singles before the last 16 stage.
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