Scottish Tory leader Annabel Goldie has warned supporters not to be complacent and urged them to fight for every vote in the forthcoming UK election.
She told her party's conference its performance in Scotland on polling day could be the key to David Cameron becoming prime minister.
And Ms Goldie said voting SNP or Lib Dem could help keep Labour in power.
The Tories, who have just one Scottish MP, have set an ambitious target to win 11 seats north of the border.
Speaking at the conference in Perth, Ms Goldie said the General Election, widely predicted in May, was a once-in-a-generation opportunity to remove Labour and deliver change.
"That's the choice - a strong and united Conservative Party under David Cameron, or a weak, divided and failing Labour government under Gordon Brown," she said.
"Let's be clear what this British general election is about - it's about electing a British prime minister, a British government and a British parliament."
Turning to her political opponents, she said: "Alex Salmond is not going to be that prime minister, the SNP is not going to be that government - voting SNP could simply keep Labour in power.
"The Lib Dems are not going to be that government - voting Lib Dem could simply keep Labour in power.
"That is why only the Conservatives can be that new government, that is why only David Cameron can lead us in that new direction."
Ms Goldie said the Tories had a vital election role to play in Scotland.
"A handful of votes in Perth and North Perthshire could win us the British general election," she said.
"That last-minute canvass in East Renfrewshire could deliver the keys of 10 Downing Street to David Cameron.
"That town hall hustings performance in Dumfries could mean a Conservative victory."
The Scottish Tory leader said: "Put simply, winning seats in Scotland could win us the British general election.
"Be in no doubt, it is going to be very close - every vote will count."
Ms Goldie went on to say "Labour's mess" on finances had overshadowed Scotland, saying of voters: "They know Labour has run out of ideas and they are sick of Labour's deceit and dishonesty."
And she accused Mr Salmond, the Scottish first minister, of abusing his position of power to fulfil his "obsession" for an independence referendum, which currently does not have enough support at Holyrood.
"I don't think that is what the people of Scotland wanted when they elected the SNP in 2007," Ms Goldie added.
Claiming Labour was a party of the past, she told the conference: "We are on the front foot, we are ready for government, we are working hard, we have purpose.
"We can win this British General Election and we can win in Scotland."