The forward missed several games for the London club earlier this season with a hamstring injury and had a further spell out after suffering a relapse.
He was back in action for Tottenham at the start of the month and completed 90 minutes against Ipswich last week in a 2-1 home defeat.
Son also missed games for his country but he started and scored in South Korea's 3-1 away win over Kuwait in World Cup qualifying on Thursday.
Son's first-half penalty took him to a half-century of international goals and joint second on South Korea's all-time list of goalscorers.
The 32-year-old thanked Tottenham and South Korea for "taking a great interest in my health and protecting me".
"I am feeling great," the South Korea skipper, who was substituted in the 64th minute as a precaution, told reporters in Kuwait.
"I am back to my normal condition. I'd like to play at 100 percent in the next match."
Son, who was making his 130th international appearance, praised his teammates for giving him "opportunities to score so many goals".
"It's a huge honor to be mentioned alongside some great names in Korean football, but the most important thing is the win tonight," said Son, who is now eight goals away from matching his country's all-time scoring record.
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.
South Korea can take another giant step towards an 11th straight World Cup when they play Palestine in the Jordanian capital Amman on Tuesday.
Coach Hong Myung-bo plans to go easy with his star man despite Son's insistence that he is ready to play a full part.
"He is currently struggling with injuries and is in a phase of repeated recovery," said Hong.
"He played 90 minutes in the last match (for Spurs) but when I watched him today, he wasn't at his best.
"I believe we need to continue protecting Son Heung-min for the future."