 On June 29, 2018, Aung La Nsang defended the ONE Middleweight title for the first time against Ken Hasegawa at in Yangon in what is now considered one of the greatest title fights in ONE Championship history.He defeated Hasegawa by TKO in the fifth round to retain the title.On October 26, 2018, he beat Mohammad Karaki by TKO via punches at in Yangon to retain the ONE Middleweight title.