Grodzisk Mazowiecki: Mathys Erhard vs Ivan Marrero

Platform comparison

Market context

The quarter-final between **Mathys Erhard and Ivan Marrero** in Grodzisk Mazowiecki is priced very differently across markets: the prediction contract is currently at **100% YES**, while sportsbook-style pricing points to Erhard as the clear favourite rather than a certainty. PokerStars lists Erhard at **1.44** and Marrero at **2.50**, which implies roughly **69%** for Erhard before vig, and Tennis Tonic also names Erhard its pick, albeit with equal opening odds of **1.84** each in that preview[13][1]. That leaves a sizeable gap between the contract’s crowd-implied probability and the more conventional pricing layer.

Comparable signals from tennis prediction sites also lean towards Erhard, but not to the extent reflected by the market. Tennis Temple’s model shows Erhard at **87.2%** versus **12.8%** for Marrero, while another Tennis Temple event page shows **82.6%** to **17.4%**; both are materially below a 100% implied outcome and suggest the contract is being treated as near-certain rather than mathematically locked[10][2]. Tennis Explorer’s head-to-head section shows Erhard leading the matchup **2-0**, and that historical edge helps explain why analysts favour him, but it does not eliminate match risk[16].

For traders, the main catalysts are simple but important: official order-of-play updates, any late schedule shift, and whether the match is completed within the settlement window. The event is listed for **15:00 UTC** on 7 August, with the market staying open until **14 August 2026**, so a walkover, cancellation or delay beyond seven days would matter more here than a routine straight-sets result[4][15]. Because the contract resolves to **50-50** if the match is not played at all or is pushed too far out, the key risk is not who wins on paper but whether the fixture is actually completed in time[15].

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.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Kalshi vs Polymarket. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

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.