Nothing moves the dial more with the transition from hard courts to clay courts than points won returning first serves.

An Infosys ATP Beyond The Numbers analysis of the four semi-finalists from the 2017 Rolex Monte-Carlo Masters against their own 2017 hard-court averages identifies the biggest improvement in any serve or return category was points won returning first serves.

The four semi-finalists in Monaco last year were David Goffin, Lucas Pouille, Albert Ramos-Vinolas and the champion, Rafael Nadal. The quartet combined to put up positive numbers in all three return categories on the clay, but their combined performance against first serves was the most noteworthy.

2017 Monte-Carlo Semi-Finalists: Combined Monte-Carlo v Hard-Court Averages

Returning first serves on hard courts is best done with a defensive strategy, blocking and absorbing the power of the first serve. The 11-percentage point jump by these four players on clay is born from standing a little farther back to return first serves, allowing them to have a slightly slower delivery to take aggressive swings at.

2017 Monte-Carlo: Four Semi-Finalists

Nadal amazingly won 49 per cent (97/199) of his first-serve return points at Monte-Carlo in 2017 against Kyle Edmund, Alexander Zverev, Diego Schwartzman, Goffin and Ramos-Vinolas. Nadal is the career leader in first-serve return points on clay, winning 40 per cent.

In Monte-Carlo last year, Ramos-Vinolas was 14 percentage points ahead of his 2017 hard-court average, with Pouille nine percentage points better, while Goffin enjoyed a seven percentage-point improvement.

The serve may travel through the air just the same on hard courts and clay courts, but once it bounces on clay, the returner can immediately employ a lot more offence against the biggest shot in our sport.