Pronóstico: National Bank Open: Marta Kostyuk vs Iga Swiatek

Platform comparison

Market context

Marta Kostyuk’s meeting with Iga Swiatek at the National Bank Open is priced as a clear underdog spot, with the crowd implying about a 9% chance on Kostyuk against roughly 91% on Swiatek. That sits well below several market and preview estimates, which have Swiatek around the mid-50s to low-70s in win probability and priced near -140 to -270 on the moneyline, while some books have Kostyuk around +116 to +220[1][3][6][13].

The historical frame is mixed: Swiatek leads the head-to-head 3-1 overall and 2-0 on hard courts, but Kostyuk beat her in straight sets at Roland Garros in May 2026, which is the main comparable result for reading upset risk[2][8][15]. Form is the other key tension. TennisTemple lists Kostyuk at 29-6 this season and Swiatek at 22-10, while Polymarket’s tournament page notes Kostyuk arrived in Toronto with straight-set wins over Madison Keys and Katherine Sebov, alongside a 27-6 2026 record and two titles[4][8].

For traders, the main catalysts are whether both players are confirmed in the round-of-16 schedule, whether any late physical issue emerges, and whether the match timing slips beyond the settlement window. The market resolves 50-50 if the match is not played, ends tied, or is delayed more than seven days from the scheduled date without a winner, so withdrawal news or rescheduling matters as much as pre-match form[4]. Current live preview pages and odds boards already show Swiatek as the likelier winner, but not overwhelmingly so, which leaves the market sensitive to any official lineup, fitness, or order-of-play update before the first ball is struck[1][7][16].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Football-specific comparison page for Pronóstico: National Bank Open: Marta Kostyuk vs Iga Swiatek. 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 (US-focused) or Manifold (play-money).

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

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Once the official league outcome is logged in the UMA Oracle (typically 1-2 hours after the final whistle), Polymarket's smart contract triggers USDC payout. To your wallet within minutes.

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

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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.