Regardless of the answer, I really just wanted to talk about how broken/glitchy it is. I believe this was recently discussed, but I had an odd experience tonight that I wanted to share. Took down a gym, left a porygon2, instantly clicked back on the gym and he had 1 battle won already. This was the first time I had ever left him so I know he didn't actually battle anything. I mention which mon it was cause one of his eyes was all black and looked like he got punched in the face. I clicked on the gym 5 times and his eye was black 3 outta 5. Still said 1 battle won evertime though. Also he was a hatch not powered up at cp 1422, dnot think he could kill 6 mons in 1 second, lol
Truth is that nobody exactly knows. There are some theories, but reality is that it is very glitchy and doesn't always registrate battles won.
From personal experience, your best call is that a defender at least kills one Pokemon and subsequently let the attacker time out with one of his other Pokemon.
