I remain mildly obsessed with Francisco Cerundolo’s second-serve stats. It started when I was writing about Jakub Mensik last month. Mensik is one of the worst players on tour at winning points when opponents return his second serve. Cerundolo is the best.
This graph compares points won when first and second serves come back. It is now five weeks old, but the numbers haven’t changed much:
Unfortunately for Cerundolo, this is not a particularly valuable skill. There’s a surprisingly weak correlation between win percentage on returns in play (for first or second serves) and win percentage overall. Men who hit a lot of unreturned serves often end up with mediocre return-in-play win rates, because they don’t have easy plus-one opportunities–those great serves don’t come back at all.
Cerundolo’s second serve almost always comes back. Only 14% have gone unreturned in the last 52 weeks. Of players with at least ten charted matches in that time, only Marcos Giron is lower. Average is 18%, and even Sebastian Baez is at 16%. The Argentinian’s second serve isn’t bad, it’s just not quite as much of a weapon, and his focus is to set up the rally in his favor.
It isn’t just about the return-in-play win rate, though. Cerundolo can rely on his second serve more than most of his peers–sometimes more than on his own first serve.
Trending up
Over the last year, Cerundolo’s second-serve winning percentage is 53.1%, good for 19th among the top 50. (That doesn’t count stats from the ongoing Madrid tournament.) Nothing special, though still a respectable number for a guy whose serve is not his foremost weapon.
In 2025–still not counting Madrid–he’s up to 54.1% and 14th place, a couple ticks behind Jack Draper. Tack on his four wins so far at the Caja Magica, and he’s up to 55.5%.
Like many guys with games tailored for clay, the gap between Cerundolo’s first and second serve stats is smaller than average. Going back to the last 52 weeks, here are the top ten smallest ratios between first- and second-serve win percentages, along with tour average and the man at the other extreme, Mensik:
Player 1st% 2nd% 2nd/1st Sebastian Baez 63.6% 50.4% 0.792 Carlos Alcaraz 73.4% 56.7% 0.772 Davidovich Fokina 67.2% 51.9% 0.772 Lorenzo Musetti 69.7% 53.2% 0.763 Tommy Paul 71.9% 54.8% 0.762 Francisco Cerundolo 69.7% 53.1% 0.762 Tomas Machac 69.8% 53.0% 0.759 Casper Ruud 71.4% 53.8% 0.754 Holger Rune 73.0% 54.9% 0.752 Alex de Minaur 73.4% 54.5% 0.743 … Top 50 Average 73.6% 52.4% 0.712 … Jakub Mensik 76.5% 46.6% 0.609
By the end of that list, you’ll have to knock the clay off your soles. This is another metric in which Cerundolo is reaching new heights this season. So far in 2025 (including Madrid), he’s won 70% of firsts and 55.5% of seconds, for a ratio of 0.793, just edging out Baez.
These narrow gaps aren’t really about good second serves. They reflect game styles built around modest first serves and strong baseline play. Most serves come back, and when they do, it doesn’t matter much which serve kicked things off.
It’s also just what happens on slower courts. The average top-50 player sees his first-serve win rate drop to 70% on clay, resulting in a ratio of 0.744–just about even with Alex de Minaur.
High seconds
The quirks that got me hooked at Cerundolo’s second-serve stats are the occasions when he wins more second-serve points than first-serve points. He did it against Tommy Paul at Indian Wells, in his semi-final loss to Ben Shelton in Munich, and again to kick off his Madrid campaign against Harold Mayot.
This is another clay-court kind of thing. Since the beginning of last season, only two men have accomplished the feat more often than the Argentinian has:
Player Matches 2>1s Sebastian Baez 76 12 Casper Ruud 91 12 Francisco Cerundolo 87 9 Mariano Navone 61 8 Davidovich Fokina 67 8 Lorenzo Musetti 81 8 Alex Michelsen 81 8 Alex de Minaur 92 8
Once again, the stat has as much to do with pedestrian first serving as it does with strong second-serve execution. Since the start of 2024, the player who has won 60% of his second-serve points most often is Jannik Sinner. Despite clearing that line 44 times, his second-serve win rate has never been higher than his first-serve mark.
When Cerundolo is at his best, no serve–first or second, his or his opponent’s–matters much. Here are his win percentages by rally length over the last 52 weeks:
Length Win% 1 to 3 47.6% 4 to 6 50.1% 7 to 9 50.7% 10+ 57.3%
The short-point stat tells us that Cerundolo doesn’t win as many quick serve points as his opponents do. Then, the longer the rally drags out, the more things tilt in his favor. Most players struggled to keep their ten-plus number much above 50%. 57.3% is outstanding, highest among any player with at least ten charted matches.
Second thoughts
None of these numbers identify any unique superpower. Cerundolo is a throwback clay-court specialist, much like his coach, Pablo Cuevas. He serves because he has to, then he launches inside-out forehands until his opponents finally surrender.
The skills I’ve isolated do a great job explaining yesterday’s defeat of Mensik in the Madrid quarterfinals. The match was close, with the Argentinian winning 94 points to Mensik’s 91. The Czech was two points from victory in the second-set tiebreak.
Yet despite occasional bursts of return aggression from Mensik, Cerundolo’s second serve never faltered. He won 21 of his 33 second-serve points, including 75% in the pivotal second set. His opponent hit 33 second serves as well, and despite averaging the same speed on those deliveries–96 miles per hour–Mensik won only 14.
That’s more than enough to explain the end result. Long-rally prowess will do the job, too. Mensik entered the match with a 11-4 tiebreak record on the season. When I wrote last month about the Czech’s performance in breakers, I pointed to his ability to keep points short, something that most players are unable to do under end-of-set pressure. Well, in yesterday’s second-set tiebreak, Cerundolo got enough balls back to push the average rally length to 5.6 strokes. He took Mensik’s biggest weapon off the table.
In today’s semi-final against Casper Ruud, Cerundolo faces a different challenge entirely. As we’ve seen, the Norwegian is another player for whom the serve is little more than a formality. Last time they met, in Miami, it was Ruud who won more second-serve points than firsts. Today’s meeting may give us more quirky stats, but the serves themselves are unlikely to tell much of the story.
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