WWE superstar David Otunga took a break from his full time wrestling gig to return to his previous career -- attorney-at-law -- and much like his "Monday Night Raw" matches ... crushed the competition.

TMZ found out Otunga returned to court Thursday morning to represent a man who believes he was wrongfully terminated and denied unemployment benefits. Otunga tells us he was repping the man in his appeal to the NY State Department of Labor.

The proceedings took place before an administrative judge who heard witness testimony and arguments from both sides.

Otunga -- who graduated from Harvard Law School before wrestling -- told us he "smoked the witness during cross examination." The judge agreed ... Otunga's client won the appeal and will now get unemployment benefits.

Otunga says he enjoys keeping his legal skills sharp, and adds ... "If the outcome of the case is any indication of how I'll do in the Royal Rumble this weekend, then it looks like I'll be the winner."