Ridge ripped into the Scottish politician for his party's "major strategic mistake" in focusing on the 48 oer cent who voted Remain in the EU referendum.
The Sky News host even teased Mr Rennie, mocking his bizarre confidence that his party will gain seats in this election.
When she said that the Liberal Democrats were drifting into obscurity, the party's Scottish leader said he wanted to "change the world" which prompted widespread ridicule online.
Ridge ripped into the Scottish politician for their "major strategic mistake" in focusing on the 48%
Tim Farron decided to pin the party's fortunes on the 48 per cent Remain camp
Ridge said: "This election was meant to be about the comeback of the Lib Dems.
"But you are polling in single figures and there is no evidence of a fightback that will see you increase your pretty meagre number of MPs."
Mr Rennie, who is a candidate for North East Fife, tried to his best to desperately spin the electoral forecasts into something positive.
He said: "We are particularly confident in Scotland, in turning the tide of the SNP. I’m very confident about this campaign. We are going to make gains."
Ridge pressed him on this, incredulously asking: "You really think you will gain seats?"
The Liberal Democrat was adamant: "Absolutely, we will make gains in this election, gains in Scotland, gains down South, gains in the West.
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"I guarantee you we will grow in this election."
The Sky News host even teased Mr Rennie, mocking his bizarre confidence
The party's Scottish leader said he wanted to "change the world"
You are going to make gains?
When quizzed on Tim Farron's decision to pin the party's fortunes on the 48 per cent Remain camp, Mr Rennie was resolute.
Ridge said: "The idea of a second referendum has been at the heart of your campaign.
"Was focusing on the Remain vote a major strategic mistake?
"Polls show that majority of those who voted Remain just want to get on with Brexit now.
Mr Rennie dismissed this and said he valued standing for principles over gaining seats.
He added: "If you just face the opinion polls, you don’t follow your principles and you don’t do what is right.
"I came into politics to change the world, not chase opinion polls".
Ridge mocked this, claiming: "That is very high-minded and moral but you won’t win many seats!
"The party is self-destructing but you're very confident."