National Bank Open: Marta Kostyuk vs Iga Swiatek

Platform comparison

Market context

Marta Kostyuk and Iga Swiatek are due to meet in Toronto after both advanced cleanly through their earlier National Bank Open rounds, with Swiatek beating Sara Bejlek 6-0, 6-3 and Kostyuk getting past Katherine Sebov 7-6(4), 6-0.[1] Tennis.com currently lists Swiatek as the projected winner at 57%, which is above the market’s 44% crowd-implied probability for Kostyuk, suggesting the market is pricing a modest underdog position rather than a coin flip.[2]

The historical frame is fairly clear: Swiatek leads the head-to-head 3-1, and she is 2-0 on hard courts against Kostyuk, which matters more here than the Ukrainian’s clay-court upset at Roland Garros in May.[3][11] That recent Paris result is the main comparable case for how Kostyuk can land a surprise, but Toronto’s outdoor hard courts and Swiatek’s stronger record on the surface are the cleaner prior for reading the current number.[5][11]

The immediate catalysts are scheduling and fitness rather than draw complexity, because the match is already set for Centre Court and the market only resolves normally if it is played and completed with a winner inside the settlement window.[2][4] Traders should watch for any order-of-play change, late withdrawal, or weather disruption in Toronto; the tournament site has already shown routine day-to-day updates around both players’ progress, and the event runs through 16 August, leaving room for delay risk if play is interrupted.[1][9][14]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track National Bank Open: Marta Kostyuk vs Iga Swiatek across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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.

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