Big Match (2014) on Netflix

Plot summary

Choi Ik-ho made his name in football and then in mixed martial arts, where he fights under the nickname Zombie. When Young-ho, his older brother and coach, vanishes, the police arrest Ik-ho as the prime suspect in a murder. Then a man called Ace telephones him. Ace designs elaborate contests for Korea's richest citizens, who bet enormous sums on games played out in the city with real people, high-tech gadgets and CCTV cameras. Joining is the only way Ik-ho can save his brother, and a woman named Soo-kyung relays his instructions. Cops and low-rent gangsters are among the opponents he has to get past.