National Bank Open: Marta Kostyuk vs Madison Keys

Platform comparison

Market context

Madison Keys and Marta Kostyuk were on court in Toronto within the last day, and the live market picture has been shaped by the fact that this is a third-round match on the National Bank Open schedule rather than a completed result. The crowd-implied 77% for a Kostyuk win sits above some pre-match projections, while Tennis.com had Kostyuk at 57% and flashscore-style previews treated her as the favourite but still noted Keys’ pedigree on faster courts.[2][3]

The historical frame is fairly clear: Keys has beaten Kostyuk 2-0 at WTA level, with both meetings coming at Wimbledon in straight sets, so the head-to-head does not support a simple ratings-only read.[1][5] At the same time, both players arrived in Toronto with usable form rather than injury-driven uncertainty; Kostyuk advanced past Katherine Sebov, while Keys beat Antonia Ruzic comfortably.[3] That is why the market sits in favourite territory rather than a near-lock.

The main catalysts now are straightforward: whether the match is officially completed, whether any suspension or weather delay pushes resolution beyond the seven-day window, and whether the tournament’s published round progression changes the advancement path.[4] The National Bank Open listings still identify the fixture as a third-round match in Toronto on outdoor hard court, so any schedule adjustment, retirement or walkover would matter more to settlement than pre-match narrative.[4][9]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews National Bank Open: Marta Kostyuk vs Madison Keys 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 Prediction Today, 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.

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