National Bank Open: Kayla Day vs Coco Gauff

Platform comparison

Market context

Kayla Day’s second-round meeting with Coco Gauff at the National Bank Open is a straightforward class test: Gauff entered as the world No. 4 and the projected winner, while Day was around No. 127 and had only just come through a tight opening match in Toronto.[1][2] Tennis.com’s match page had Gauff at an 87% projected win chance, which is broadly consistent with the market’s current 0% YES pricing on Day.[1] The first five listed H2H records showed no prior meetings, so there is no recent stylistic history to lean on for an upset case.[3]

The comparable-case frame points to a quick read on where the edge sits. Day’s run to this round was built on a three-set win over Diane Parry, but reports around the match described that as only her second tour-level win of the season, with most of her 2026 success coming on the ITF circuit.[4][19] By contrast, Gauff’s recent hard-court baseline remains stronger, and her Toronto record cited by preview coverage is solid enough to support a heavy favourite’s price rather than a coin-flip.[4] That makes the market’s only real vulnerability the small sample size of Day’s form versus a top-five opponent.

The main catalysts now are scheduling and any last-minute player news. The tournament’s own Wednesday order of play listed Day v Gauff on Centre Court, with a 12:30 pm start block, so any weather delay or card reshuffle would matter more to timing than to the underlying matchup.[8] If the match is not played at all, is pushed beyond the settlement window, or finishes via an administrative tie/void scenario, the market can still resolve 50-50 under the stated rules. Any withdrawal, medical issue, or late change to Gauff’s load management would be the only developments likely to move this materially away from the current favourite setup.[8][9]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Sports-specific comparison page for National Bank Open: Kayla Day vs Coco Gauff. 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

When do sports markets resolve?

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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.