ATP Surface Advantage Index (2025)

Quantifying which players gain the biggest boost from surface-specific conditions

Tennis has always been a sport of surfaces. A player who looks untouchable on slow clay can look ordinary on a skidding hard court; a servebot who dominates indoors can suddenly struggle to generate traction on dirt.

At TennisTrove, we wanted to measure that phenomenon properly, not through reputation or eye test, but through data.

The result is the Surface Advantage Index (SAI): a clean, Elo-based metric that captures how much a player over-performs (or under-performs) on a given surface compared to their overall level.

Below, we outline how SAI works and which ATP players show the strongest surface-specific boosts heading into 2025.

What is the Surface Advantage Index (SAI)?

SAI measures the difference between a player’s surface-specific core Elo rating and their weighted global core Elo.

In simple terms:

SAI = Surface Core Elo − Global Core Elo

Where:

• Surface Core Elo = a player’s performance rating only on a given surface (hard, clay, grass).
• Global Core Elo = a weighted average of their core Elo across all surfaces, using matches played as weights.

A positive SAI means the player is better on that surface than their baseline global level.

A negative SAI means the opposite: the player struggles there relative to their overall ability.

This gives us a standardized way to identify clay and hard court specialists, and players who outperform their baseline in certain environments.

2025 ATP Surface Advantage Leaders

Ranking the biggest surface specialists by SAI

Below are the players whose SAI values show the strongest positive surface-specific boosts relative to their global level.

A minimum surface sample of 15+ matches played was applied to reduce small-sample noise.

Clay Specialists — Largest Clay Boosts

Luciano Darderi — SAI: +146.19

Darderi leads all players with the most dramatic clay-specific boost in our entire dataset. His clay core Elo sits 146 points higher than his global baseline, which is a massive, tour-defining surface differential. His 2025 season reflects that advantage perfectly: Darderi claimed multiple ATP titles, surged into the ATP Top 30, and captured the Grand Prix Hassan II, reinforcing his status as one of the breakout clay presences on tour. His heavy topspin and physical rally tolerance on dirt translate directly into this elite SAI value.

Flavio Cobolli — SAI: +105.06

Cobolli’s Elo profile confirms his emergence as a high-end clay threat. His clay rating sits 105 points above his global level which is one of the strongest surface lifts on tour. After a difficult start to 2025, he flipped his season on European clay, winning his first ATP title in Bucharest, then capturing a career-best ATP 500 trophy in Hamburg, and rising into the ATP Top 20. Cobolli’s clay results and SAI data align perfectly: his game gains clear traction on dirt.

Filip Misolic — SAI: +103.22

Misolic is one of the most statistically reliable clay over-performers in the field, with a +103 SAI backed by substantial match volume. Across 2024–2025, he delivered his best career results on clay: a strong showing at Roland Garros (reaching the third round), multiple Challenger titles, another ATP quarterfinal run, and a steady climb into the Top 100. His SAI reflects consistency, not volatility — a classic clay-first profile.

Tallon Griekspoor — SAI: +90.06

A genuinely surprising entry. Griekspoor is often viewed as a fast-court shotmaker, yet the numbers reveal a +90 SAI on clay, which is a significant overperformance relative to his all-surface baseline. His broader 2025 campaign has been outstanding, producing his 100th career win, a semifinal run in Dubai, and a statement victory over world No. 2 Alexander Zverev at Indian Wells. The clay SAI suggests he has a deeper, more adaptable clay game than his reputation implies.

Juan Manuel Cerúndolo — SAI: +71.02

Cerúndolo’s +71 SAI quantifies what fans and analysts have seen for years: he is one of the purest clay specialists on the ATP Tour. His 2025 clay season included his first Masters wins, a third-round run in Madrid, and a final in Gstaad highlighted by wins over David Goffin and Casper Ruud. His return to the Top 100 mirrors the clay-heavy efficiency captured in his SAI.

Hard-Court Specialists — Largest Hard-Court Boosts

Daniel Rincón — SAI: +111.46

Rincón owns one of the strongest hard-court lifts in the entire dataset. His +111 SAI shows a clear, significant performance boost on quicker surfaces. In 2025 he added another headline moment by winning the Rafa Nadal Open Challenger, delivering the title at the Academy where he trained as a junior, with Nadal himself watching courtside. Rincón’s lefty patterns and aggressive baseline tempo scale exceptionally well on hard courts, and the data backs that up.

Jannik Sinner — SAI: +65.51

Sinner already owns a reputation as one of the premier hard-court players in the world, and his +65 SAI reinforces that dominance. Even at a sky-high global Elo level, Sinner still exhibits a meaningful performance bump on hard courts, reflecting how well his clean ball-striking, down-the-line patterns, and serve-aggression pair with faster surfaces. His SAI captures the statistical backbone of his hard-court supremacy.