In an online game if there is only one human player left but in the end they lose to a bot, I think that player should still be declared the winner and have the game count as a win and not a loss in their win/loss count.
It often happens that towards the end of a game all of the other players have quit and been replaced by bots. For many reasons, the bot/s can be too strong to overcome. As far as ranking points are concerned, games like this are effectively wins. That is, how a game affects your ranking points is determined by your finishing order relative to the other human players. I think the same idea should be applied to the win/loss count. A game in which a player finishes ahead of all other human players should be counted as a win, not a loss.