The implied probability of Vilius Gaubas winning his US Open qualifying match against Harry Wendelken fell sharply on Polymarket, from 73.5% an hour earlier to 27%. Catcher Predict monitoring measured the move at 46.5 percentage points in the sub-market titled "US Open, Qualification ATP: Vilius Gaubas vs Harry Wendelken." The shift highlights a substantial change in market positioning, and relevant breaking news should be considered when assessing the move.