The part of the video that makes sense is when he says this technique is useful when the ball is on top of you and you need more space. On many/most balls this won't be necessary is you've prepared early. But we all know Oscar doesn't believe in early preparation. He likes to run his mouth about how he taught Guga the one-handed backhand. From what I've seen from other sources, Larry Passos was Guga's personal coach, who taught him the one hander. Oscar probably taught clinics where Guga was there. As usual, Oscar is exaggerating his connection to a real player, and taking credit for someone else's hard work.