Same as being beaten by anyone.
Seeing as I'm not all that amazing at either shooters or strategy which are the most common competitive games I'm quite used to losing, doesn't bother me much and what little is there is directed purely at myself when I know I did something stupid. Can't say I really care whatever the gender of the person who beat me is, I see losing more as a sign that I personally have to improve than anything to do with the person I'm playing against.
Seeing as I'm not all that amazing at either shooters or strategy which are the most common competitive games I'm quite used to losing, doesn't bother me much and what little is there is directed purely at myself when I know I did something stupid. Can't say I really care whatever the gender of the person who beat me is, I see losing more as a sign that I personally have to improve than anything to do with the person I'm playing against.