They would spiral in combat and that particular year I watched them in the garden several times descend oblivious to anything but each other, then eventually when it did dawn on them, shoot off about 1 metre from the ground in separate directions....
so one constructed net, and a cool night gave me this the next day..then released hopefully none the worse for it's experience.. Incidentally, I've never seen sparring males do the same since... maybe the word got around!!