In 1966 he won men's singles at the All England Open Badminton Championships, then considered the unofficial World Badminton Championships, defeating Japan's Masao Akiyama in the finals. This came during a run of four straight appearances in the All England finals from 1965 through 1968. He lost hard-fought matches to Erland Kops in '65 and '67 and to Rudy Hartono in '68. Tan was a member of four Malaysian Thomas Cup (men's international) teams including its world champion team of 1967. He won numerous major international singles titles during the mid- and late 1960s including the Danish Open, the US Open, the Canadian Open, and the Malaysian Open. He won both singles and doubles at the British Commonwealth Games of 1966.