Livesport Prague Open, Qualification: Sofia Costoulas vs Ayla Aksu

Platform comparison

Market context

Sofia Costoulas has already defeated Ayla Aksu 2–0 in their WTA encounter at the Livesport Prague Open, confirming the Belgian’s advancement in the qualification round [1]. This result validates the 100% YES crowd-implied probability on the prediction market, leaving no ambiguity regarding the match outcome. The settlement window, ending in July 2026, will formally close the contract once the official tournament records are updated, though the real-world event has concluded.

Historically, prediction markets with 100% implied probability on completed matches rarely diverge from sportsbook lines, as the outcome is already known and irreversible. In comparable cases, such as post-match resolution on Polymarket versus Kalshi, the implied probability aligns perfectly with the actual result, eliminating arbitrage opportunities. Traders observing this contract should note that the divergence between prediction-market pricing and sportsbook odds is negligible, reflecting the certainty of Costoulas’s victory.

Key catalysts for this market are now limited to administrative confirmations, such as the official WTA match report and tournament committee validation. No further player announcements or schedule dependencies remain relevant, as the match has been played and completed. Recent coverage from Tennis Majors confirms the 2–0 scoreline, providing the definitive source for settlement [1]. Traders should monitor the official WTA database for the final record update, which will trigger the market’s resolution to “Sofia Costoulas.”

Sources: 1

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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 Kalshi vs Polymarket. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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.