I can deal with most flankers in 1v1 long enough for help if I can't finish them. All of them except decent Genji's. They're always too fast for me.
Anyway team chat helps alot. Cause real talk: dps players are dense as fuck about positioning in battle, flankers, knowing where their team is, and how to stay on the point. They all have tunnel vison. You have to tell them whats up all the time or they sure as shit won't know. Tell them if they're moving to far out, if you see a flanker coming, if they should rely on health packs cause your dead atm, if an weak flanker is fleeing for them to finish. Treat them all like Helen Keller and your teams will start doing better