The match between the two nations was played in front of no fans of either side or any foreign media.
The fixture at the Kim Il-sung Stadium in North Korea ended goalless despite South Korea's position 76 places above their neighbours in the FIFA rankings.
But Son was happy simply to avoid picking up an injury, per Dan Kilpatrick of the Evening Standard:
"The match was very aggressive—it's a huge achievement just to return safely without being injured."
Korean Football Association vice-president Choi Young-il further elaborated that the match was "like war," and he had "never seen such [aggression] in football."
Swedish ambassador to North Korea, Joachim Bergstrom, one of the few spectators in attendance, provided apparent footage of a heated altercation between the two sides:
Spurs manager Mauricio Pochettino will be relieved Son avoided any fitness problems while he was on international duty.
The 27-year-old is one of Tottenham's most important attackers and has already registered two goals and two assists in six Premier League appearances this term.
However, per Kilpatrick, Son is unlikely to be ready to start in Saturday's clash against Watford.
Spurs are desperate for a victory after suffering four defeats in their last five outings.
Watford should be the perfect opponents to bounce back against as they are winless in eight games so far this term and rock bottom of the table.