It definitely is. I've studied the service for a long time as my former coach was very good at it. He brings the paddle upwards and to the left of the ball, but uses a diagonal stroke meaning he is putting left spin and top spin, but on the left side of the ball rather than the back side of the ball. With enough spin you are able to make the ball seem like underspin on the first bounce as the ball will rotate slightly downwards giving an underspin bounce, but on the second bounce the ball will rotate around it's z axis and bounce upwards making it a topspin and leftspin service. Just put your mouse on 0:18 and watch how the ball bounces then click it again and again. You'll start to see what's happening just from clicking it a few times.