Last season I had a 4v5 ranked with an AFK-farm JG and an actually AFK Bot lane.
Luckily we had an enchanter support and surprisingly impactful Ivern 
Top. I was 
mid. We managed to win before late game.
I know this was only Bronze/low Silver, but still felt great :D
What was your favorite 4v5 win in Solo Queue?
I had a game where my bot lane was doing really bad and I was afraid the game was over. The enemy ADC was 8/0 by the 11 minutes and they got the first bottom turret. But in the meantime I was starting snowballing having 4 kills under my belt, Ezreal (the enemy ADC) started poking me under my tower, I took that opportunity to kill him and got a massive shutdown gold, that helped me to snowball even harder. After a while our ADC left the game, but everyone was performing well so that didn't make a big difference. That Ezreal was bad, after those 8 kills he never killed a single person and died 10 time. I was doing insanely well, never died, over 20 kills and great creep score. After a while they surrendered. I was playing Talon as well, once you start snowballing, it's hard to be stopped.
Had a game where top went afk but I was playing Jarvan and had MF and Sona bot. Enemy team grouped and I hit R and every other ult came out and cleaned up.
My last 4v5 win was way back in Season 7. I was Leona support with a Jhin. Can't remember who it was that left but they left like 7 minutes into the game. Me and that Jhin just tore that shit up. It was a pure fuckin stomp. Never seen anything like that since.
