After 29 minutes, Dejan Kulusevski gave Spurs and South Korea the lead, but Son made his mark in Seoul on his return home.
After 38 minutes, he curled a shot into the upper corner and tapped home a cross from Kulusevski to give his team a 3-0 advantage at the half.
Stanislav Iljutcenko scored twice in the first five minutes of the second half while Team K League, who had substituted their whole squad at halftime, responded with two goals.
Spurs manager Ange Postecoglou was encouraged by it to alter and replace Timo Werner’s pass was volleyed home by Will Lankshear to it.
James Maddison struck the post in injury time as Spurs held on to win despite Oberdan’s response for the hosts with nine minutes remaining.
On Saturday, they return to preseason action when they play Bayern Munich in Seoul at 12:00 BST.
Newcastle overcame a difficult night against the 2022 Asian Champions League winners by winning 4-1 against Urawa Red Diamonds in Japan.
The Magpies led 3–0 as Alexander Isak scored his third goal in as many preseason games. However, the hosts tied the score in the 23rd minute when a Rio Nitta backheel smacked in off the post.
