Ruth Davidson dismissed the fall in Tory support in opinion polls as something that "always happens" in election campaigns.
The Scottish Tory leader also said the prospect of Jeremy Corbyn in Number 10, with John McDonnell as his chancellor and Diane Abbott as home secretary, would focus voters' minds.
She spoke out with less than two weeks to go until the June 8 General Election, with several polls showing the Conservative lead shrinking, including one which put Theresa May's party just six points clear.
An ORB poll for the Sunday Telegraph had Tories down two points in the past week on 44%, six points ahead of Jeremy Corbyn's Labour on 38% (up four points).
That equals Labour's best rating since Mr Corbyn became leader and would see him comfortably outpoll Ed Miliband and Gordon Brown's election results if repeated on June 8.
Ms Davidson told the Sophy Ridge on Sunday programme on Sky News: "As a veteran of six Scottish or UK wide elections and two referenda the narrowing of the polls always happens around this time and it focuses people's minds.
"People at home will be thinking actually in two weeks time Jeremy Corbyn could be in charge of the country, Diane Abbott could be the home secretary charged with keeping us safe, John McDonnell might be in charge of your pay packet."
She added: "Theresa May is Prime Minister, I hope she continues as Prime Minister, in three weeks' time the first day of negotiations for Brexit are going to happen and we will either be led by Theresa May of Jeremy Corbyn.
"And I absolutely, seven days a week, twice on a Sunday, think Theresa May is the best person in that job.
"There is a big issue that's happening, it's not going to be easy the Brexit negotiations but it absolutely requires the right people to take us in there because the difference between a good deal and a bad deal will affect all of us in this country.
"I honestly don't know what Jeremy Corbyn's policies for Brexit are, I've never heard him stand up in a speech and read them out, I've never heard him say what he wants to pursue.
"He could be prime minister in two weeks time and I don't know what he would do on Brexit and neither does the country."
Scottish labour leader Kezia Dugdale told the same show Mr Corbyn was an asset to Labour's campaign "because of the platform he's standing on".
She said: "What we've got is a radical Labour manifesto with a plan to transform this country and right at the heart of that manifesto is a plan to raise living standards.
"Only the Labour party is offering that so those types of policies that are about lifting people up and helping them get on in life is right at the heart of what Jeremy Corbyn stands for."
On Brexit Ms Dugdale insisted there is a stark difference between the stance of her party and the Conservatives.
"First and foremost we say that we would guarantee the rights of EU nationals living in the UK," she said.
"That's incredibly important here in Scotland where so many of them work in the NHS and our universities.
"Secondly we've said we would rip up the Great Repeal Act to focus instead on jobs and the economy, making sure that we can protect workers' rights."
Meanwhile Scottish Liberal Democrat leader Wille Rennie argued there was "a big opportunity in the next 10 days to make the real point that what we need is a brighter future for this country".
On Brexit he claimed: "The Conservatives will just agree to anything because they're absolutely committed to delivering a Brexit no matter the consequences.
"I think the British people should have the final say, not just a few Conservative ministers in the cabinet room.
"It should be the British people because they should have the right if its bad for jobs, bad for security, bad for our environment, bad for the NHS, I think they should have the right to say 'no, we do not want this deal'."
He said he was "very confident" about the election campaign, arguing in Scotland his party is "turning back the tide of the SNP".
Mr Rennie stated: "We're going to make gains, we're going to make gains in this election.
"In Scotland we're going to make gains, down south we're going to make gains.
"I'm not going to start naming numbers but what we can actually guarantee is we're going to grow in this election campaign, because we've got that package of policies which is going to be popular."