What would happen in a battle of Felix Felicises (?)

Question

If two equally skilled and similar (in terms of physique and metabolic processes) wizards played against each other in a game of chance (dice, card games, whatever) after drinking the same amount of felix felicis of same quality, who would win?

Would the felix felicis in their systems cancel each other out, so that it would be as if neither of them drank anything at all?

Or is it possible that one would ultimately come out as a winner due to very slight variations in how their body would react to felix felicis?

Or is it something else entirely?

Answer 1

Felix would lead them both away from playing with each other, as that would be the most lucky scenario for each of them (Thanks @Deltharis).

If you consumed some Felix and went to a gambling table, it would be highly unlucky if you met another person who had consumed Felix at the same table. This would violate the basic effect Felix brings upon you.

If you're wondering how Felix would know that another person would arrive at the same table having consumed Felix as well, that's basically how the potion works. Taking an instance from the sixth Harry Potter book, Harry consumed Felix to get some information out of Slughorn and, instead of heading to Slughorn's office where he'd most likely find him, headed toward Hagrid's hut, on Felix's direction. He then took a detour towards the Herbology greenhouses on another prod from Felix. He happened to run into Slughorn there, by the greenhouses. How did Felix know Slughorn would be at the greenhouses? That's just how the potion of luck works.

Answer 2

After some fan analysis regarding all instances of canon use, the following two points appear to be self-consistent in the use and application of this potion:

Felix Felicis causes the drinker to have a limited period of good luck, during which they are likely to to succeed in all endeavours in which success is possible.

This is accomplished not through direct application of force or granting the drinker any extraordinary powers, but by inspiring the drinker with a favorable pathway through the circumstances.

^{_{(emphasis added)}}

So the question, "If two equal wizards played against each other in a game of chance after drinking the same amount of felix felicis of same quality, who would win?" becomes moot.

"Success" for one of them is not possible, and it's entirely through chance that one or the other would come out ahead. It quite possible, though, that the one thing the question doesn't take into account, the desires of the individual players, would make a difference.

For instance, one may merely be playing for money, while the other might be playing for fame. It's quite possible that the outcome of the game could give both of them their desires, even if the game appears to pit the one against the other. If, for instance, the fame desiring champion was influenced by Felix to choose to give the money to the loser before the game started (perhaps because he feels he's cheating?), then both potions could work together to cause the fame desiring one to win, while the money desiring one would feel lucky at the end once the winner privately gave the winnings to the loser - as he merely desired the fame.

Perhaps something outside the game provides an influence. One of them might have some "friends" or relatives who, upon seeing their friend win, would pester them or complicate their lives, and so losing might actually be luckier than winning - though in this case the loser might in fact believe the potion didn't work.

Unfortunately there are too many other influences, and too little known about the potion, to make a good objective answer to this question.

At best the result is undefined.