Longshot but please help:)

[Chimaera]

Too much HP to cut down without the spammable magic blast and fireball.

Use a full Lv. 75 intellect set with as much INT as possible. I doubt a Lv. 79 capped server even has set armor, but I wouldn't know. Consider your build full INT or the +25 SPR option (paired w/ completed license on your hatchling wand+9) Use jewelry that increases your basic magic damage. I hope you see where I'm going with this.

Empowerments — bold is absolute, the rest is optional/interchangeable.

Magic Blast: +5 Power/CD
Spam this skill. Alternate fireball and firebolt in between.

Fireball: +5 Power/CD
Hopefully you can get a nice crit.

Firebolt: +5 Power/CD
Still powerful enough to do some damage.

Frost Nova: +5 Power/CD
A good alternative (than icebolt/iceblast) to slowing the fighter down at the BEGINNING of the battle or while you're kiting. Some people think your AoEs are useless in PvP: they're not.

Drain Mind: +5 Duration/CD.
Duration is a must. If you plan on making this a long fight, consider cooldown. You will reach about 17.5 seconds total if this skill is chain casted and you have your full Lv. 75 intellect set.

Stifle: +5 Duration/CD.
If you have some nice DEX gear paired with the INT you desperately need, stifle can help you get out of a stun. But cast frost nova/inferno at your feet before trying something like that. Consider both duration and cooldown.

Hopefully the fighter will use a 2h/axe instead of a shield as that would reduce their magic defense. However, if you want to last through a stun (while he's stifled) pray he uses a 1h + shield or you're dead.