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.

Remember, Masvidal campaigned for Trump during the 2020 election cycle ... and they clearly have a pretty tight friendship.

When Trump finally emerged from the tunnel and was spotted by the 20K+ crowd -- there were some jeers -- but the response sounds overwhelmingly positive.

Last week, Dana told us that Trump would NOT be sitting in a luxury box ... he'd be right behind the UFC honcho, Octagon side.

However, the ESPN cameras didn't show Trump ... even though they showed a bunch of other A-list celebs (Kourtney Kardashian, Justin Bieber, Dave Chappelle and more) who were in the house.

Of course, internet conspiracy theorists have been having a field day ... speculating why Trump wasn't shown during the broadcast.

Bottom line ... #45 was there, and seemed to get a whole lotta love from the UFC crowd.