Garak would probably have superior character shields as a fairly important secondary character so he would be less likely to die against a random Jem'Hadar.
Garak is a spook, he prefers to kill through more elegant methods, poisons, bombings, phaser shot to the back in a dark alley. Garak would probably consider it a failure if he found himself in a position having to fist fight a Jem'Hadar with no weapons.
Given Jem'Hadar are meant to be super-soldiers they should win but given that Sisko managed to beat one down and he is a human who in Trek are very average in terms of strength, power and intelligence then Garak could do the same. If it is the Jem'Hadar that so easily overwhelmed the Defiant in to occasions I'd go with the Jem'hadar.