National Bank Open: Jakub Mensik vs Ben Shelton

Platform comparison

Market context

Polymarket is pricing this contract at **0% YES** today, so the market is effectively treating Jakub Mensik advancing over Ben Shelton as a near-impossibility despite the event still being unresolved on-chain. Because the market settles in USDC on Polygon through conditional tokens, the key practical question for holders is not the betting line itself but whether the match is actually completed, since a cancelled match, tie, or a delay beyond seven days from the scheduled date can force a 50-50 outcome under the market rules.

That zero price sits in sharp contrast to the pre-match tennis market, where Shelton was the bookmaker and model favourite rather than a runaway certainty. Tennis Tonic listed Shelton as its pick to win in three sets, while market averages on Tennis Temple showed Shelton shorter than Mensik across several books, and Polymarket’s own sports pages have shown Shelton trading as the stronger side in related markets for this match.[1][2][10] For a trader reading the contract, the important point is that a 0% quote on Polymarket often reflects a very one-sided expectation, not a literal certainty; if the match has already started, the path to a YES requires Mensik actually advancing, while any official non-completion outcome can still shift value through the settlement rules.[3][8]

The catalysts to watch are straightforward: official ATP and tournament scheduling updates, any start-time change, retirements, walkovers, and whether the quarter-final is completed within the seven-day window tied to the resolution mechanics. Recent previews placed the matchup in Montreal’s quarter-final round and noted Shelton’s stronger outright position, which means the live trigger for this contract is less about pre-match opinion and more about whether the fixture is played to a clear advance decision at all.[11][13][18]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track National Bank Open: Jakub Mensik vs Ben Shelton across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

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's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.