Wireless mesh networks have attracted extensive research interests in recent years. With the maturity and pervasive deployment of IEEE 802.11a/b/g technology, 802.11 DCF protocol is considered as a promising candidate for constructing the backbone of wireless mesh networks. In a multi-channel multi-interface wireless mesh network, point-to-point 802.11 wireless link can provide the highest throughput; hence it is critical to understand the 802.11 throughput performance in a point-to-point configuration. This paper presents a simple yet precise Markov model for the analysis of point-to-point 802.11 link performance in terms of saturation throughput. Different from previously proposed analytical models, our model does not assume a constant and independent collision probability. Our analytical model is validated by computer simulations for both 802.11b and 802.11g configurations.