Samsun: Koki Matsuda vs Gabriel Debru

Platform comparison

Market context

Koki Matsuda’s quarter-final against Gabriel Debru in Samsun is the real-world event behind the contract, and the market is still pricing almost no chance of a Matsuda win despite the match being listed in live tennis feeds and pre-match preview pages. That is a clear divergence from the broader tennis market, where Tennis.com’s projected winner model has Debru at 68% and Matsuda at 32%, while other live score sites are carrying the fixture as in progress or scheduled rather than settled.[10][4][5]

The historical frame is thin: the pair have no prior head-to-head record, so traders are leaning more on recent form than direct matchup history.[1] Debru’s recent numbers are modestly stronger in aggregate, with Tennisstats showing a better 2026 win rate and a better last-12-months record, but Matsuda has also been competitive and comes into the event after straight-sets wins in Samsun in earlier rounds, which helps explain why analyst models are not unanimous but still favour Debru.[1][16] In comparable cases, prediction markets often drift away from a near-zero price only when a listed favourite withdraws, the match is not played, or score feeds show a stoppage that forces the contract into its fallback 50-50 outcome.

The main catalysts are administrative rather than tactical: whether the quarter-final is completed on court, whether the official schedule shifts, and whether any retirement or walkover changes the settlement outcome. Flashscore, SofaScore and Livescore all show the fixture attached to 31 July with live or match-centre status, which matters because a start without completion can still settle the contract if one player advances on retirement, while a cancellation or delay beyond seven days would push it to 50-50 instead.[2][5][15] In practical terms, any late injury report, withdrawal notice or updated order of play is more important here than serve stats or surface splits.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Samsun: Koki Matsuda vs Gabriel Debru across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Best Prediction Markets, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Best Prediction Markets. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.