Versus Dehaka you would probably want to attack the hero first and not move to far from your own wall because if you get side jumped, minions might help block the tongue.
Same way you’d prefer to duel a Tracer by hoping their small bodies would block the bomb or in case of Malthael, avoid killing enemy minions on purpose so you can receive extra sustain while fighting a player. I would keep my distance and let minion waves stack, lure him in if possible, instantly kill everything and receive some help in return form your own. No one is surprised that dueling Fenix can be hard but you have Kneel, Peasants to help a little a bit later in the match.
