Dude wagered on a 1.22 odd game. I mean sure it is a big "win" if you look at the amount, but dude wagered 101k to get there, he didn't really make that much of a return for a gambling game. If he lost this, he would have needed at least 4 more games like this to win in order to recoup it, so it is not really a profitable bet when the outcome is just a little return when the loss could be losing it all.

Kudos to them for being brave, but the "biggest win!" is actually someone betting a lot for a small and likely to be won game. Ajax scoring in the first half could have happened or not, that is a risk you take, but it was such an obvious thing for every football watcher that, nobody is shocked about it.