Watched by a crowd of 49,097 at Singapore's National Stadium, the visitors took the lead after nine minutes when Son was denied by a fine save by Hassan Sunny but Joo Min-kyu retrieved the loose ball and laid it off for Lee to fire home a fierce right-footer.

Singapore twice went close to levelling the score as Hami Syahin's header forced a save from Jo Hyeon-woo and Ikhsan Fandi headed over from close range.

But the Koreans extended their lead in the 20th minute when Kim Jin-su's cross from the left was headed in by an unmarked Joo.

Singapore came from two goals down to draw 2-2 with China in their last home game but the South Koreans put the game away with a spell of three goals in four minutes at the start of the second half.

Son made it 3-0 in the 53rd minute when he received the ball on the right flank and cut inside Harhys Stewart before firing a low shot past Hassan.

Lee then capitalised on poor defending a minute later to add his second before Son got Korea's fifth shortly afterwards in a near carbon copy of his first goal.

Son was denied a hat-trick when Hassan tipped aside another curling effort.

But late goals by substitutes Bae Jun-ho and Hwang Hee-chan sealed an emphatic win for the South Koreans who secured top spot in Group C with a game to spare.