On one level, darrell is right - though with a Robilar's Gambit build this is easier said than done.
So, in general, you don't attack a character with Robliar's Gambit. You do the following:
a) You use missile weapons or spellcasters, generally with distributed multiple attackers.
b) You attack with large sized creatures that are using reach weapons, thereby escaping retaliatory strikes. If they have improved combat reflexes, so much the better.
c) You immediately go to grapple, preferably with improved grab, preventing normal combat.
The other option is to fight cheese with cheese, though this is generally a losing proposition against a decent power gamer.