This paper proposes a mechanism to combine link-adaptation and transmit power control (TPC) in IEEE 802.11a WLANs. The link-adaptation and TPC algorithms try to maximize the goodput of the WLAN, while minimizing transmit power. The algorithm runs at the sender, but it relies on feedback from the receiver. The latter notifies the sender about the signal-to-interference-plus-noise-ratio experienced in previous transmissions, allowing a prediction of the channel status. An extension of the algorithm for multicast is also presented. The implementation of the proposed mechanism in IEEE 802.11a/h/e WLANs is discussed and its performance evaluated.