National Bank Open: Aryna Sabalenka vs Shuai Zhang

Platform comparison

Market context

Polymarket is pricing Aryna Sabalenka at **94%** to advance over Shuai Zhang, which leaves only a small tail for an upset or a market-specific settlement outcome on the USDC contract running on Polygon. In plain tennis terms, that is a heavy favourite line: third-party previews and betting boards are broadly consistent, with Sabalenka listed around -1429 to -2500 and modelled win chances mostly in the low-to-mid 90s.[1][2][13][15]

That level fits the wider comparable case for this matchup. Tennis.com’s event page has Sabalenka as an **88% projected winner**, Dimers puts her at **90.4%**, and String Tension’s Elo view is even stronger at **96.9%**; historically, market prices in this band tend to track straightforward straight-sets expectations rather than a genuinely coin-flip contest.[3][5][13] For Polymarket users, the key point is that the contract resolves on the actual advancement outcome, not set score, so a dominant favourite can still trade below 100% because walkovers, cancellations, or an incomplete match can push settlement to the 50-50 fallback under the rules.

The main catalysts are procedural rather than tactical: confirmed start time, any pre-match withdrawal, and whether the match is actually played rather than postponed beyond the seven-day window. Public listings place the match around 11:00 PM EDT on 6 August, and tournament schedule changes can matter more than player form at this stage because the market’s resolution depends on the official result or the contract’s fallback mechanics if play does not happen.[1][7][9][10] Recent pricing sources have not flagged a meaningful injury or withdrawal issue, so the live watchlist is the order of play, court assignment, and any late news from the tournament desk.[10][16]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

UK Frequently Asked Questions

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.