Guillermo Vilas has been dominant on clay, posting 681–173 across 854 matches (79.7% — exceptional). Few players in the Open Era have sustained that level of dominance across a full career on clay. With 49 titles, among the most prolific clay court champions in the Open Era: Buenos Aires, Gstaad, Hilversum, Louisville and 28 more.

At Grand Slam level (Roland Garros): Guillermo Vilas has been outstanding — 75–19 (79.8%) across 94 matches. Winning more than 7 in 10 Grand Slam matches on clay is the benchmark of an all-time great on this surface.

77 finals reached on clay — won 49, lost 28 (solid 64% conversion) — consistently getting to finals and winning the majority is a hallmark of elite performers on clay. 108 semifinals. 131 quarterfinals.

vs. Top 10 on clay: 36–55 (39.6%, 91 matches). Top 10 opponents have represented a clear ceiling on clay; addressing that deficit is the single biggest lever for improving the overall record here.

By format on clay — best-of-five: 151–52 (74.4%); best-of-three: 530–120 (81.5%). Slightly stronger in three-set contests on clay, though the five-set record is still respectable.

Dominant season: 1977 — 98–5 (95.1%) from 103 matches. A campaign of 98 wins on clay in a single season is among the best single-season records the surface has seen — the clearest benchmark of what is achievable at peak level.

Historic: 53 consecutive wins on clay — one of the longest winning streaks on this surface in the Open Era. To sustain that level across so many matches demands physical and mental consistency that very few players in history have matched.