I wish there was a save point between that Rude/Elena fight and the Rufus/Darkstar one. I rage quit this weekend as I didn't feel like looking up how to beat him and now have to do it over again
Same thing happened to me
In my case it wasn't a rage quit, I was just super low on MP with Cloud (since you don't get a break between fights and I wasn't expecting another fight right away) and figured I'd use an Ether before fighting Rufus. Well, I did, but only near the end of the 2nd Rufus/Elena fight after I had to beat them again.
This game definitely likes to you with checkpoints sometimes