RIHANNA HANGS WITH KENDRICK BY DAY ... Jay-Z By Night

Rihanna's the Wonder Woman of hip-hop, even down to her wardrobe ... slaying the stage with Kendrick Lamar during the day in all white and then later crashing the Jay-Z concert looking stunning in black.

Rihanna started her day in L.A. by performing with Kung Fu Kenny at the packed TDE Annual Christmas Concert in Watts performing "Loyalty."

She then showed hers by catching Jay-Z's concert at The Forum nearby in a little black leather dress. 

In other words, Rihanna's average Thursday... better than everybody else's.