The limitations of backscatter communication (BSC) can be overcome by exploiting advantages of the multiple-input-multiple-output (MIMO) technology at the reader. In this paper we propose a novel maximum eigenvalue based BSC detection protocol for a monostatic MIMO reader to minimize the underlying bit error rate (BER). Specifically, two orthonormal sequences for the backscattering coefficients (BC) at the single-antenna tag are used to exploit the rank-one property of the cascaded BSC channels in monostatic settings for detection at the reader without requiring any help from the low-power tag in channel estimation. Lastly, the efficacy of the proposed detection protocol is numerically quantified while shedding key insights on the impact of the key simulation parameters like rice factor, orthonormal sequence length, array size, and signal-to-noise-ratio on the achievable BER.