Under the tutelage of Mike Wolf, with whom he began working at age 11, Sock massaged the machinations of his still awkward service motion in which he brings his racket back only partway rather than the old-school, back-scratching position. (He still managed to hit 26 aces in four matches in Delray Beach and has been recorded serving as fast as 141 miles per hour.) His forehand is much the same but far more effective, appearing almost like a slingshot that is pulled back only halfway. But with enormous spin added to the power, it is a much-feared shot.

“I heard a stat that he hits the hardest with the most rotation of spin on the forehand, on average, on the tour,” Young said. “He’s a good athlete and a great competitor, and he utilizes his strengths and works around his weaknesses. Put those things together, and you’ve got a really good player.”

Sock credits Wolf for that potent spin.

“Low to high, reach for the sky — that’s what I was taught when I first started tennis,” he said. “He taught me how to turn the ball over and rotate the other way.”

Wolf, who travels sporadically and now leaves the day-to-day work to Hahn, played down his role in shaping the stroke.

“I call him Picasso because he has so much natural ability,” Wolf said. “I believe in feeling the ball, but I don’t prohibit someone from doing what’s natural. So, more or less, I stayed out of the way and tried not to mess things up with him.”

Whatever the formula, it has propelled Sock on a steady climb in his results and his rankings. He has already won two major titles in doubles, the 2014 Wimbledon men’s title with the Canadian Vasek Pospisil and the 2011 United States Open mixed doubles with his fellow American Melanie Oudin. At the Rio Olympics, he captured two medals: a gold in mixed doubles with Bethanie Mattek-Sands and a bronze in men’s doubles with Steve Johnson, both Americans.