riddle me this?

[Lakie]

Ill leave the last one open for anyone else to have a go...

A Boss finds himself with two potential candidates for a job, after evaluating he cant decide who to hire so he proposes a challenge to both candidates.

The Game is this, at the round boardroom table each person has an huge stack of coins (exceeding the amount needed for the game), one at a time, each candidate places a coin on the table and this happens back an forth. The first person who can not put a coin on the table loses the job and the winner is hired.

The coins muct remain on the table and cant be moved, the coins must be layed flat and completely resting on the table surface, the coins cant overlap etc etc

A Coin toss decide who goes first, the first person places a coin in the exact middle of the table and they know theyve won no matter what the other person does

How does he/she know he/she's won?