After being forced to retire from his Australian Open quarter-final against Marin Cilic in January with a hip injury, Nadal sat out the hard court season.
The Spaniard, who recently returned to world No 1, is expected to make his return this weekend for his country’s Davis Cup clash against Germany in Valencia.
After that, he will step up his preparations for an 11th French Open crown when he plays at the Monte Carlo Masters, with the Barcelona Open and Madrid Masters to follow.
Nadal will need to successfully defend those titles in order to stay at the top of the men’s game heading into Roland Garros.
There appear to be very few secrets about the 31-year-old’s stunning success on the red dirt.
But O’Shannessy thinks the effectiveness of his returning where he’s won more points than any other opponent on the surface, has been key.
“Overall, there is not one serve or return metric that Nadal has a superior career ranking on hard courts over clay courts,” O’Shannessy told ATP World Tour.
“Step one for the Spaniard is to keep the serving side of the equation on clay as close as possible to his serving on hard. He has certainly achieved that.
“Step two is to put up unprecedented numbers when he returns serve.
“When returning on clay, Nadal typically stands way back to let the speed of the serve slow down for greater return consistency and also to allow more time to deliver a full-blooded swing at the ball.
“He then looks to improve his court position up closer to the baseline as the point unfolds, looking to crush his forehand from locations all over the court.
“Serving against Nadal on hard court is always challenging. Serving against him on clay is downright formidable.”