Heres an example for ya. Did it all the time on production (while I was there)
Regular bok bok template
120 swords
120 bushy
120 ninja
100 hiding
95 meditation
90 tactics
75 stealth
Run some weapons like a bokuto with HLD/lightning and a warfork with HLD SSI fireball
You see a mage, attack. Give chase, LS LS a few times as to not give away your immediate combo tactics and to get the HLD on them. Then throw a shurken/dart at them. Get them with the poison, immediately follow up with a bleed attack. At this point, after LS'ing a couple times you're not going to scare the mage enough to make them go on the defense and heal. Now once down maybe 20-30 hit points, throw your darts/bleed attacks and that immediately puts them on the defense and trying to heal. With the disruptions from bleed/poison you can then nerve strike/LS and then Deathstrike...Once you deathstrike, most decent mages will sit still so they dont take the 50 damage. Once you see them sit still immediately hit your conflag potion (target relative location macro) and they'lll be forced to move or take a decent amount of damage from the conflag.
After all this, you can pretty much waiste a mage with those steps. Of course its not going to go exactly to plan. But the most important part of fighting a mage from a dexxer perspective is keeping the disruptions up...aka the bleed and poison. Bleed is killer to a mage. Maybe even use a weapon that has mortal strike.
This is normal damage output
LS - 5-9 w/additional lightning damage of 11ish (crit could be 30 damage)
LS - same as above (could be 30)
Poison/bleed - self explanatory
Nervestrike - weapon damage 5-9, special damage 20-25 plus spell damage plus paralyze
LS - same as above (could be 30)
DS - 5-9 (10 additional damage if they don't move...45-60 if they do)
conflag pot - 4-5 damage per second....
You can see how the damage adds up real quick!!!
In the end if you can't kill the person. You should definitely be able to hold your own against any mage (unless they're a necro/spellweave) Those waffles are just hard to kill on a dexxer temp...but they can't kill you either