National Bank Open: Sara Bejlek vs Iga Swiatek

Platform comparison

Market context

Polymarket is pricing Sara Bejlek to beat Iga Swiatek at **4% Yes**, which implies the market is assigning roughly a 96% chance to Swiatek on the contract side. On-chain, that position is expressed through USDC on Polygon and settles via conditional tokens, so the key question is not just who is favoured, but whether the match is actually completed in a way that triggers the listed winner-or-50/50 outcome.

The current price sits close to the broader pre-match consensus. Independent tennis pricing around the same meeting has put Bejlek at roughly 5% and Swiatek at about 95%, while bookmakers have generally shown Bejlek around 7.0 and Swiatek around 1.10, a gap that is typical for a heavy favourite facing a much lower-ranked opponent.[1][2][4] That makes the 4% contract price look broadly in line with off-market expectations rather than an obvious outlier. In comparable mismatches, the underdog’s path is usually limited to taking a set or capitalising on an unusually poor start from the favourite, not a high-frequency outright upset.[2][5]

For traders, the most important catalysts are any late schedule changes, court assignment updates, and whether the match begins and finishes inside the settlement rules. The market description states that if the match is not played, ends in a tie, or is delayed beyond seven days without a winner, it resolves 50/50; if play starts but does not finish, the advancement outcome controls settlement. At the moment, match listings show the pairing as a live or scheduled event around 6 August, so the immediate watchlist is simple: official order-of-play confirmations, any postponement, and the final result if Swiatek’s status changes in play or by retirement.[1][7]

Sources: 1 · 2 · 3 · 4 · 5

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

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.

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.