An extremely common technial error people make on their first serve is to open up the racket face too soon on the upswing. Andre's position in both frames is known as the "waiter's tray" position because it resembles how a waiter carries a tray on the palm of his hand.

Instead of the "waiter's tray" position, Andre needs to get in the "Big L" where the butt cap of the racket points to the net and the strings face the side fence (not up to the sky). This will allow him to get the twising motion - what we call pronation - that gets the racket to travel fast into contact.

Andre's body position is excellent in this sequence. In fact, his body position looks identical to Nalbandian's. But his racket orientation will undermine his ability to pronate into the ball properly.