I've been playing a few games with two friends of mine, these two friends were gold and bronze before they started playing again after they had been getting sick of comp because of their ranks and stopped playing.
Anyways, when they finally returned to comp they decided to troll, so they decided to play symmetra and lucio only, on both attack and defense (to do that tactic where lucio speed boosts and the Symmetra becomes super fast and gets a fucking god like killstreak). But to their surprise they actually won with that tactic, so they keept doing it and they keept on winning until they finally became platinum and high gold, I think their ranks now are like 2763 and 2476, by only playing symmetra and lucio. Then I joined in and played two games with them, we won those as well.