Son hits 50th international goal as South Korea edge closer to World Cup
Spurs and South Korean skipper Son missed last month's qualifiers with injury but celebrated his return with a first-half penalty in a 3-1 win against Kuwait.
Victory left South Korea comfortably top of Group B with four wins and a draw after five matches and on course for the 2026 World Cup in North America.
The top two teams in each of the three Asian qualifying groups will reach the showpiece in the United States, Canada and Mexico.
With this phase of qualifying approaching a halfway point, South Korea took a 10th-minute lead in Kuwait when striker Oh Se-hun rose highest to powerfully head home.
Nine minutes later it was 2-0 to the visitors after Son - playing in his 130th game for South Korea - won the penalty and then picked himself up to bury it with minimum fuss.
Mohammad Daham struck on the hour to halve the deficit with a delicious half-volley.
But substitute Bae Jun-ho, who had replaced Son, made the game safe for South Korea with their third 14 minutes later when he refiled in at the near post.