Neither one of those is "bittersweet" tbh. The second one seems to have a silver lining because you could rationalize that you were potentially second best (though bracket-style elimination doesn't really determine who's best in the first place; the whole thing's very flawed).

"Bittersweet" involves an actual upside that wouldn't be realized otherwise. I.e. The loser being able to go home to his sister's wedding. "Whelp, maybe we're 2nd?" is not bittersweet it's just an optimistic take.