"There are always players that you have to battle for playing time, no matter which team you play for," Son told reporters. "There's no reason why I should fall behind in the competition. To win the battle, I have to get better myself."
Tottenham finished third in the standings last season and will be playing in the champions League this term.
Son is also one of three 'wild card' players in South Korea's 18-man squad at next month's Rio Olympics and said he felt a weight of responsibility as one of the seasoned players.
"I am older and more experienced than other players, and so I think I have to be their leader," the 29-year-old said.
"I hope everyone will take the Olympics seriously. All the other countries will go for a medal, and we have to compete with a sense of responsibility."
South Korea face Fiji, Germany and Mexico in Group C at the Olympics and are expected to win their first match but Son has warned his team mates against complacency.
"People seem to think we are supposed to beat Fiji, but I don't think we should get ahead of ourselves," Son said.
"You have to play the game. As important as the Germany match will be, I think winning the first match is the most crucial."
(Reporting by Shravanth Vijayakumar in Bengaluru; Editing by Ken Ferris)
