Barron Trump made his campaign rally debut Tuesday night as former President Donald Trump hosted thousands of supporters to his golf club in Doral, Florida and made a huge claim about the 18-year-old.

'This is the first time he's ever done it,' the former president said, looking around the front rows of the crowd. 'Where is Barron? Stand up. Look at him! ... You're pretty popular. He may be more popular than Don and Eric. We gotta talk about this. Hey, Don, we've gotta talk about this huh?' 

The 78-year-old ex-president said 'welcome to the scene, Barron,' and cracked that his youngest son 'had such a nice, easy life - now it's a little bit changed,' earning raucous cheers.

But Trump led the rally with a new challenge for President Joe Biden, 81, whose reelection campaign has been imperiled by his poor debate performance late last month. 

The ex-president first said he wanted to debate Biden again - 'next week' - which would coincide with the Republican National Convention. Biden is due to debate Trump a second time already, but on September 10. 

Trump also said he wanted to play Biden in a game of golf - and staked $1 million on the deal. 

'I'm also officially challenging Crooked Joe to an 18-hole golf match right here. On Doral's Blue Monster considered one of the greatest tournament golf courses anywhere in the world,' Trump said. 'It will be among the most-watched sporting events in history.' 

Trump said it could be bigger than the Ryder Cup or the Masters. 

'I will even give Joe Biden 10 strokes aside, 10 strokes, that's a lot. That means 20 strokes in case you don't play golf,' he continued. 

'And if he wins I will give the charity of his choice - any charity that he wants - 10 million dollars,' the ex-president added. 'And I bet he doesn't take the offer.'

The Biden campaign quickly clapped back, calling Trump's rally 'deranged.'