Here's the Donald Trump entrance you did NOT see on TV ... with the former POTUS arriving at the arena for Conor McGregor's UFC 264 fight -- and getting a huge ovation from the packed crowd.
TMZ Sports obtained video of DT arriving at T-Mobile Arena midway through the main card ... and being greeted by his longtime friend, UFC prez Dana White.
As Trump and White begin walking towards the arena floor, Donald sees Jorge Masvidal ... and the 2 men exchanged a bro hug.