Professor Lucas Lepri demonstrates a high single-leg takedown, emphasizing adaptation based on the opponent's stance. He begins by explaining that when the opponent has the same lead leg, a step with the back leg is crucial to disrupt their balance. He shows how to drive forward, using hand pressure to push the opponent off-balance before securing the single leg. Conversely, when the opponent has the opposite lead leg, he demonstrates stepping with the front leg to close the distance effectively. He stresses the importance of keeping the head inside to avoid potential chokes, and demonstrates how to secure a deep grip on the opponent's ankle. He then transitions the grip by switching hands, and explains how to use the knee as a support if the opponent’s leg is heavy. Lucas shows how to trap the opponent's leg by controlling the back of the knee, and completes the takedown by driving forward and turning the opponent, ensuring a successful finish.