Mauricio Umansky's trying to have a good time outside the courtroom ... hanging with a new friend while a legal battle rages.

The 'Real Housewives' star was spotted leaving the Sunset Towers Hotel Friday night with Destiny Herzog -- a star on season 6 of "Love Island USA."

The two laughed and smiled together while driving away from the establishment ... which boasts the celebrity hotspot Tower Bar & Restaurant.

Herzog's clearly got Umansky's spirits up ... and he needs it -- because according to court documents, Mauricio's father's longtime girlfriend, Simin Tabibnia, fired back at the lawsuit filed by Mauricio’s family. 

Remember ... Mauricio's sister accused Simin of financial elder abuse of her and Mauricio’s father, Eduardo -- alleging Simin spent more than $400K of Eduardo's money on various personal items.

Simin's response said, “The alleged transfers occurred during an 18-year intimate romantic relationship between Simin and [Eduardo]" adding "payments were voluntarily made by [Eduardo].” 

Eduardo got a restraining order against Simin last year. Simon attempted to get her own order of protection, but was denied. 

Despite the drama, it's great to see Mauricio getting out there and livin' life ... even if he's not actually on an island!