When someone is extremely fighty...
... and competitive to you, keep securing your solar plexus chakra cause usually that kind of energy attack most that part of us. Mental energies start to push each others ego's and that is how any conflict arise.
Sametime don't engage in it with reaction but understanding - let the wise and therapeutic side of you, which understans humans psyche and emotions prevail: watch situation like you are third part, some observer or a consultant, not like it is happening to you and provoking your ego materials.
That is you will bring peace into the situation and keep your balance and, most important, keep spreading the vibe of peace on another people.