National Bank Open: Marta Kostyuk vs Iga Swiatek

Platform comparison

Market context

Marta Kostyuk’s meeting with Iga Swiatek is priced like a live underdog spot rather than a coin flip, with the crowd at 44% for Kostyuk. That sits against a head-to-head that has largely favoured Swiatek: one set of records shows her leading 4-1 overall, while other match-history trackers list four completed meetings with Swiatek taking the bulk of the recent hard-court and clay encounters.[2][3][5] For programmatic traders, that usually means the market is anchoring to past matchup data, but not treating it as decisive enough to push Swiatek into a near-lock.

The most useful comparable case is the most recent French Open match, where Kostyuk beat Swiatek 2-0 on clay in May 2026, reversing the older pattern of straight-set Swiatek wins in Indian Wells, Cincinnati and earlier Roland Garros meetings.[2][9][15] That matters for automated models because it shows the pair has both a long-run favourite and a recent result that can distort naive head-to-head weighting. A simple bot workflow would therefore separate surface, recency and format, rather than relying only on the headline H2H count.

For the next few days, the main catalysts are whether the draw and schedule hold, whether the match is actually played on the originally listed date, and whether any ATP/WTA order-of-play changes push it beyond the market’s settlement rules. The market resolves to 50-50 if the match is cancelled, ends level, or slips more than seven days without a winner, so parsers should monitor official schedule updates and live score feeds, not just pre-match odds.[10] If the match begins but is not completed, the advance rule decides the outcome, which makes partial-play states especially relevant for conditional-order logic and bot alerts.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews National Bank Open: Marta Kostyuk vs Iga Swiatek 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 Polymarket Bot UK, which mirrors the Polymarket order book at 0% fees.

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.

UK Frequently Asked Questions

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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.

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