A greater likelihood decoder, a method of deriving a reduced substreams maximum likelihood (RSML) decoded symbol vector and a multiple-input, multiple-output (MIMO) receiver incorporating the decoder or the method. In one embodiment, the decoder includes: (1) a suboptimal decoder that analyzes a received symbol vector to generate substream indicators and a decoded symbol vector estimate, (2) weakest substreams decision logic, coupled to the suboptimal decoder, that receives the substream indicators and selects weakest ones thereof and (3) subspace search logic, coupled to the suboptimal decoder and the weakest substreams decision logic, that further selects a reduced substreams maximum likelihood (RSML) decoded symbol vector from a subspace of decoded symbol vector candidates derived from the decoded symbol vector estimate and the weakest ones.