National Bank Open: Marta Kostyuk vs Madison Keys

Platform comparison

Market context

Marta Kostyuk’s meeting with Madison Keys in Toronto pits a lower-ranked, counterpunching all-court player against a bigger-serving former top-five opponent who has already beaten her twice on the WTA level, both times in straight sets at Wimbledon. The head-to-head therefore leans towards Keys, and that history matters because their last two matches were both decided without a final-set swing, which reduces the case for a big upset based on recent familiarity alone.[1][2][6]

The crowd price around 57% for Kostyuk looks slightly more aggressive than the matchup history would suggest, so traders should watch whether the market is leaning on surface and current draw context rather than direct evidence between these two. One useful comparison point is that Keys has generally held the edge in recent form and ranking strength, with the official tournament listing showing Keys at No. 22 and Kostyuk at No. 11 in singles, while match databases show Keys leading the rivalry 2-0 and winning their 2024 Wimbledon meeting 6-4, 6-3.[1][13] If either player has any late fitness issue, that would matter more than the headline probability because the market resolves on advancement, not just whether the match is completed.[5]

The main catalysts are the final match status, any walkover or retirement ruling, and whether the contest is actually completed before the settlement deadline; if the match is cancelled or left unresolved beyond seven days, the market goes 50-50. Because this is a live tournament setting, any change in the order of play, court assignment, or late withdrawal would be more important than general form, and the tournament’s own match page is the cleanest source for that latest status.[5][13]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Sports-specific comparison page for National Bank Open: Marta Kostyuk vs Madison Keys. Polymarket's live quote (Polygon order book) plus platform attributes for the three reference venues. Sports markets reward liquidity — Polymarket and Betfair are materially deeper than Kalshi or Manifold.

Resolution & payout

Sports markets typically settle on official final-whistle plus league confirmation. Polymarket uses UMA Optimistic Oracle with a source URL per contract — usually official league data feeds or ESPN/Soccerway. Two-hour dispute window, then smart-contract payout in USDC.

FAQ

What are live sports odds on Polymarket?

Some top-tier matches stay open during play — you can trade the half-time probability in the 70th minute. Polymarket mid-prices update second-by-second; any frontend mirroring the order book shows the same movement.

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How fast do sports winnings settle?

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What's the difference between match odds and outright odds?

Match odds cover a single game ("Bayern beats BVB"). Outright odds are long-term aggregates ("Bayern wins the league"). Outright markets have deeper liquidity; match markets have faster resolution.

Can I import form data and lineups?

This page shows the live Polymarket quote as an implied probability. Form data and lineups must be researched separately via sports data providers (e.g. Soccerway, ESPN, FBref) — we surface the market probability, not the sport analysis.