While baselessly claiming that Democrats won elections because of fraud, Mr Giuliani bellowed to the crowd: “Who hides evidence? Criminals hide evidence, not honest people!”
He continued: “Over the next ten days, we get to see the machines that are crooked, the ballots that are fraudulent, and if we're wrong, we will be made fools of. But if we're right, a lot of them will go to jail.”
Mr Giuliani then suddenly yelled: "Let's have trial by combat!" to lacklustre cheers from the crowd.
"I'm willing to stake my reputation, the president is willing to stake his reputation on the fact that we're going to find criminality there!" he added.
"Is Joe Biden willing to stake his reputation that there's no crime there? No."
Mr Giuliani then went on to claim, citing an unnamed "expert" that last night "the votes were deliberately changed" in favour of the Democratic candidates Jon Ossoff and Raphael Warnock in the Georgia Senate run-offs claiming that "the same algorithm that was used in cheating President Trump and Vice President Pence".
"You noticed they were ahead until the very, end right? Then you noticed there was a little gap. One was ahead by one per cent, the other was ahead by two per cent, and GONE!" Mr Giuliani yelled, clapping his hands together.
The former mayor also baselessly claimed that voting machines have been programmed to favour Democrats for years.
However the last time that a Democrat won a Senate seat in Georgia was Zell Miller in 2000 and the state last voted for a Democrat presidential candidate in 1992 with Bill Clinton.
"It's matter of scientific proof, we need two days to establish that," Mr Giuliani said.
"This was the worst election in American history," he added. "This election was stolen in seven states. They picked states where they had crooked Democratic cities and they could push everybody around, and it has to be vindicated to save our republic. This is bigger than Donald Trump. It's bigger than you and me."
Some Trump loyalists in the House have said they will reject the Electoral College certification of president-elect Joe Biden and VP-elect Kamala Harris on Wednesday.
However those same members still voted to seat their Republican colleagues from states that they claim were plagued by voter fraud, New York Magazine reported.
In Georgia, Reverend Raphael Warnock defeat Senator Kelly Loeffler for the first of Georgia’s two Senate seats. Fellow Democrat Jon Ossoff declared victory over incumbent Senator David Perdue, although the result was not yet official.
If Democrats win both of Georgia’s Senate seats, it will deliver the upper chamber back to the party, meaning Congress and the White House are in Democratic control for the first time since president Obama took office more than a decade ago.
A 50-50 Senate with Vice President-elect Kamala Harris breaking ties will make it dramatically easier for Mr Biden to get his cabinet picks through the Senate.
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