Chinese star Lin, who won the last of his world crowns in 2013, overcame Hong Kong's Vincent Wong Wing Ki 21-17, 21-18 in Glasgow.

"I really enjoyed today's match," said 33-year-old Lin, who was taken to three games in his two previous matches.

"I am very happy that I managed to minimise my opponent's performance today. It was good to get it done quicker today and I expect to perform fully to my 100 percent tomorrow."

Son, the world number one from South Korea, beat India's Kidambi Srikanth 21-14, 21-18 to guarantee his first world medal.

"Today I am really happy with my performance because this is my first semi-final," said Son.

"Srikanth was coming back in the second set and won seven points in a row and I was getting very nervous. I was just telling myself, 'One point at a time.'

"If I had lost the second one, who knows what might have happened?"