Fonseca vs Cerundolo: Argentina Open Recap

forehands — serves — stretch-shorten

João Fonseca defeated home hope Francisco Cerundolo 6/4 7/6 in the final of the ATP 250 Argentina Open on Sunday to clinch his first ATP title. Fonseca is the 10th youngest ATP Winner since 1990.

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The two most destructive forehands in the draw made their way to the final this week. Based on Tennis Insights’ 2024 data, Cerundolo (left green box) and Fonseca (right green box) occupied the who’s who of big-hitters territory:

Green circle includes Alcaraz, Rublev, Shapovalov, Berrettini, Cilic, Medjedovic, and TSW.

In line with other modern greats, we see the extended/neutral wrist position, and the upright racquet head above the hand in both men.

Fonseca wasted no time dealing the first blow, breaking in the opening game with a couple of blistering forehands from deep on his third break point opportunity.

It’s always the young guys with technical gunpowder possessing a shooter’s mentality:

But Cerundolo would break straight back, much to the home crowds delight, to get things quickly back on level terms. Off the ground the ball striking and aggression from both men off both wings was great to watch. Heavyweights.

However, one of the stark differences that was noticeable throughout the match was how much livelier Fonseca’s serve was. The Brazilian was getting the ball incredibly high, forcing Cerundolo to play with more height on his return as the ball was arriving above his strike zone despite standing from the corporate seats.

Fonseca didn’t have any skill issues mincing the ball from above his shoulders:

Look at the leg drive and body rotation on these two.

That’s massive. That exact same loading position before striking, where the wrist is extended/neutral so the strings face the back fence and the racquet head is pointing to noon, is reminiscent of so many great forehands: Thiem, Nadal, Djokovic, Alcaraz, Sinner, Wawrinka, Cerundolo, young Federer (but eastern points the strings to the side).

Some people have been asking me how Fonseca gets so much power. He hit the hardest forehand at the Australian Open (181 km/h) and regularly torches every forehand he can get set on.

It’s likely he is decently fast-twitch in the muscles, but the answer is largely technique. Perhaps better than anyone right now, Fonseca is able to create an incredible stretch-reflex in his forehand:

What’s happening here? On the left Fonseca is starting to drive his legs, which will uncoil his body up and forward in a counter-clockwise fashion, but at the same time this happens, the arm and hand goes backwards and flips the racquet back and down on a clockwise path (red arrow). It’s this move that is the source of his power. The racquet’s inertia and subsequent drop due to gravity stretches his muscles in the chest, arm, and shoulder in the exact opposite direction his body and arm are wanting to go. His brain is telling his hitting arm muscles to swing forward (internal shoulder rotation), but the technique of the racquet going down and backwards actually forces the muscle to lengthen (external rotation). This lengthening of the elastic elements is what engages the stretch reflex: an involuntary muscle activation of the stretched muscle, so now Joao’s internal shoulder rotation (forward swing) is happening much faster than he could have ever hoped without such heavyweight technique. More to come in Death of a Forehand Part IV.

Cerundolo is no slouch in this regard. He can step on a forehand when he wants to, and it’s largely a case of similar technique.

Technique is really just a form of technology. You can use it to leverage your capabilities beyond what is possible without it, just as the fastest runner can’t keep up with a mediocre cyclist. That’s why I’m prone to saying that tennis is a backswing game. How you set up for shots dictates what kind of tech you’re playing with.

So when Cerundolo’s serve is regularly sub 180, and Fonseca’s is touching 220, you know it isn’t because of some magical serving muscles.

Similar to last week’s Rotterdam recap between de Minaur and Alcaraz, we see the fate’s of both men’s serves reveal themselves before being struck:

An excerpt from that piece is just as relevant this week:

These screenshots were taken at the moment the leg drive was initiated, which you could say is the start of the serve swing in earnest (ground reaction forces start the swing). First of all, look at the different orientations of their bodies. Alcaraz Fonseca is more turned away from the court with his hips, torso, and shoulders, meaning he can uncoil more when he drives his legs and right hip up and around…Then we can see the different hitting arm and racquet structures. Alcaraz’s Fonseca’s shoulder is far more internally rotated, so he has more space to build speed as he externally rotates it, which helps create that stretch-shortening cycle as he internally rotates it into impact once more.

Notice how Cerundolo doesn’t begin to drive the legs and torso until the racquet is already well behind his head and already dropping, whereas Fonseca’s leg drive starts with the racquet still on his hitting side. Again, The Brazilian is engaging a much more explosive stretch reflex by building more speed in the opposite direction of his leg drive.

Given the firepower of both off the ground there were also plenty of dropshots (good and bad) and overall what is exciting about Fonseca is that he looks at home slicing the backhand, playing the drop shots from both sides, and moving forward to the net. Cerundolo has great hands and is pretty decent in this department himself, but I think he was outclassed today by the younger Brazilian.

There were patches of good rallies, and patches of the match where the drop shots and forehands were erratic. That’s pretty much expected from Fonseca’s end; there’s plenty of misses that you can just chalk up to the kid trying to redline. And who wouldn’t at 18 with the biggest forehand in the game? Calibrating his limits will be a work in progress.

I liked this forehand to forehand battle that finished with another blistering winner:

Any chance he gets he often just goes nuclear. I mean, 30-30 is a big point:

Huge rotation of the body.

And then there was that delpo-esque crosscourt winner in the tiebreaker:

The tie-breaker performance, after failing to serve it out twice at 5-4 and 6-5, was pretty impressive: five winners and just one error by my count (a defensive slice pushed long). In front of a boisterous and pro-Argentinian crowd, the young fella handled it incredibly well.

The win puts Fonseca at 13th in the (very) early stages of the race. I had Fonseca finishing top-20 if he played a full year, and so far that looks to be very much on track. An excerpt:

One reason I think this could work is if Fonseca got hot during the Golden Swing — a section on the calendar full of clay 250s (and a 500 in his native Brazil) that have historically allowed emerging and lower-ranked players to find tour success.

Fonseca is slated to play Alexandre Muller in his home event at the Rio 500 on Tuesday. Conditions are slow and muggy there, and given how much this week must have taken out of him — physically and emotionally — I’d be surprised if he mustered another deep run. With that said, I think Indian Wells is about the clayiest (not a word) hard court event on tour, so it will be interesting to see if he can keep this form up through the North American hard court swing.

I’ll be back with a Doha or Rio (or both!) recap next week. See you in the comments. HC.