Ljubljana quarterfinals, 18 September 2026: Samson and Sobolieva finish what they started, Barthel plays like 2013

The quarterfinals in Ljubljana have arranged themselves rather neatly. One match is a rematch that never properly finished, another is a former tour champion of 36 playing the cleanest tennis of her week against a 20-year-old who grew up on this surface, and two more hinge on something less glamorous than shot quality: who still has legs. The clay here has rewarded patient construction, yet the players who have looked best are the ones refusing to let rallies settle.

What I like about the day is that nobody in it is a finished article. Mona Barthel is rebuilding a level she once took for granted, Alice Tubello is rebuilding a body that has been through six operations, and three of the eight quarterfinalists are barely out of juniors. I'll take these four in order of play:

08:00 — Sobolieva — Samson
08:00 — Barthel — Ristic
08:00 — Basiletti — Gorgodze
09:30 — De Stefano — Tubello

Times are UTC.

Anastasiia Sobolieva — Laura Samson

These two already have a shared afternoon they would both rather redo. They met at Targu Mures on clay at the end of July, and the scoreline reads 4-2 and retirement in Samson's favour — the kind of result that settles nothing and lingers anyway. Sobolieva has spoken of trying not to dwell on what is at stake and simply playing her best tennis, and that seems to be the spirit of her Ljubljana week: "I tried not to think too much about what was at stake; I simply tried to play my best tennis" (24tv).

Her two wins here, over Lea Boskovic 6-2 7-5 and Denisa Zoldakova 7-5 6-4, were orderly rather than thrilling — she kept finding her depth at the ends of sets instead of scrambling. Samson's route was rougher: an easy first round against Lucija Ciric Bagaric, then a proper mess against Weronika Falkowska, a 6-7(6) 6-0 6-3 win in which she lost a tight opener and then simply took the match off her opponent. The reset was the impressive part; the drain is real. At 18 she has already won six finals at the Challenger/ITF level above $10K without losing one, and her clay numbers this season are near-identical to Sobolieva's, which tells me the gap is temperament, not surface.

The tactical question is court position. Samson is dangerous the moment she steps in and turns a neutral ball into pressure, so Sobolieva needs height and depth into the backhand, making the Czech create pace from behind the baseline. Sobolieva has the fresher body and the tidier week; Samson has the bigger ceiling and, having come from a set down twice this summer, fewer doubts when things get uncomfortable.

I lean Samson, but not by much and not quickly. To my eye this is a three-set afternoon: the first difficult patch will tell us how much of Falkowska she left on court. Over 21.5 games looks the sounder read than the winner, and Sobolieva at +1.5 is a perfectly respectable place to be.

Mona Barthel — Mia Ristic

Barthel is 36, ranked outside the top 200, and currently hitting the ball better than anyone in this draw. She dismantled Radka Zelnickova 6-0 6-4 and then did the same thing to Francesca Jones, a top-110 player, by the same score — and the first set was as close to total control as you will see on clay. She took the ball early, changed direction without overplaying, and never let Jones build the heavy physical exchanges she prefers. In Montreux, Fiona Ferro had kept her from dictating at all. In Ljubljana, where she is now 5-1 across her career, the timing has come back.

Ristic's week has gone the other way round, from nervy to calm. She survived Martina Colmegna 7-5 7-6(3), then pinned Miriam Bulgaru behind the baseline for a 6-3 6-3 win that never invited a comeback — a decent answer to the flat 1-6 3-6 loss to Lina Gjorcheska in Antalya just before this. Clay is her home: 44 wins in 2025 and 31 already this season, and she moves on it like someone who has never doubted where the next ball is going.

There is no head-to-head, but there is a useful clue: on hard courts this summer Barthel beat Laura Samson 7-5 6-3, so the older German still has the first strike to hurry a teenager. The counter is obvious — Ristic has to make her hit from shoulder height and on the move, and offer nothing short through the middle. Barthel's answer, apart from depth and redirection, is the drop shot, which Ristic invites whenever she defends too far back.

The market makes Ristic the favourite at 1.68, and I understand why — legs, surface, age. I'm just not sure the price respects how Barthel played against Jones. If the rallies stay short this is the German's match; if they stretch past six or seven shots, it's the Serbian's. That's too fine a line for me to call confidently, so I'll say only that Barthel at 2.03 looks generous and the under on 21.5 games is the part I'd trust least.

Noemi Basiletti — Ekaterine Gorgodze

Basiletti has spent this week looking less like a surprise and more like a player who belongs. She held her nerve to beat Lola Radivojevic 7-6(7) 6-4, then played forward from the start against Julie Struplova and won 6-2 6-3 without the match ever becoming emotionally complicated. She learned the relevant lesson at a higher level earlier in the season: "Here, you always have to go and take the point yourself" (SuperTennis). Her coach Federico Maccari frames the rest of the job plainly — "She was born with talent, and that talent then has to be developed" (OA Sport) — and says the work is as much about decisions under pressure as about strokes.

Gorgodze, meanwhile, has taken the scenic route. She came through Maria Lourdes Carle 7-5 6-7(2) 6-4 and then Lucie Havlickova 7-6(4) 1-6 6-3, losing the middle of that match completely before rebuilding her patterns in the decider. That is 34-year-old know-how at its best, and it has cost her a great deal — she has also been playing doubles here, and her clay season sits below break-even at 15-17, a long way from the 20 career titles she has collected on the way up. Left-handed variation, changing heights, dragging a right-hander across the ad side: those are her tools, and they are exactly the tools that persuade young opponents to overhit one ball too early.

Basiletti is the fresher and, right now, the clearer-headed player, and at 1.65 I think she is rightly favoured. But the -2.5 handicap asks her to be ruthless against someone who specialises in staying alive, and Gorgodze has already shown twice this week that losing a set means nothing to her. I expect Basiletti through in a match with more than 20.5 games in it, quite possibly three sets.

Samira De Stefano — Alice Tubello

This is the quietest quarterfinal and the most purely clay-based one. De Stefano was being pushed around by Arantxa Rus in the first round before she stopped defending passively, started changing direction earlier, and turned 1-6 into 6-3 6-3. Then she carried that aggression straight into a 6-1 7-5 win over Barbora Palicova — the same Palicova who had beaten Tubello from a set down in Montreux. Nothing predictive in that, but it does remove any aura from the other side of the net.

Tubello has been the steadier of the two here, beating Vivian Wolff 6-4 6-3 and then keeping Dalma Galfi from ever building an attacking sequence in a 6-3 6-4 win. Two matches, no deciders, and a level that holds through the closing games — which is the difference from Montreux. Her clay record speaks for itself: 22-5 last season, 31-13 this one. And her presence at this stage remains slightly improbable by her own account. "It's an unexpected wild card after six operations," she said of her Roland Garros chance this year (Apple Podcasts), having once thought: "I told myself that perhaps it was the end and that I needed to move on" (Tennis Actu).

The key is whether De Stefano can be aggressive without being predictable. Tubello is excellent at absorbing pace and redirecting it, so a diet of the same big ball down the same line will simply come back faster. If the Italian varies direction and occasionally brings Tubello forward, the Frenchwoman's comfort disappears. The market can't separate them either, at 1.833 and 1.85, and neither can I with any conviction — I'd give Tubello the narrowest edge on this surface and on the cleanliness of her week, and I'd expect a long, patient match rather than a short one.

Barthel's late spring and the price of a three-setter

Two things interest me most about this day. The first is whether Barthel's demolition of Jones was a fine afternoon or a genuine return of level — against Ristic she will be asked to reproduce it with far fewer free points. The second is arithmetic of a plainer kind: Samson and Gorgodze both spent three sets getting here, and quarterfinal mornings are unforgiving to tired legs, however good the tennis in them was.

If I had one match to sit with, it would be Sobolieva against Samson — a rematch of something that ended with a retirement in July deserves a proper finish. The exact numbers and the specific calls on all four are the AI cappers' territory, and they do that work on the individual match pages, where they get as concrete as this sport allows.