Supergirl wins and with ease.
The F4 wouldn't have any chance without prep against a character that can take them out in any number of ways. This would be tantamount to having four mounted Knights from the middle ages try to take on a fully armed F-15E fighter-bomber, at night, that has a targeting pod (that can even pick up the horsemen using their bodyheat in the night) over the Iraqi desert. The knights wouldn't even know what killed them.
Same thing here.
No chance!