John Swinney has insisted the Hamilton by-election is a “simple choice” between his party and Reform UK, while Anas Sarwar claimed the seat will be a fight between Labour and the SNP.
Both party leaders have been campaigning in the South Lanarkshire Holyrood constituency on Wednesday on the eve of polling day.
They held campaign events within half-an-hour of each other in Hamilton town centre, gathering with activists outside party offices.
Voters in Hamilton, Larkhall and Stonehouse go to the polls on Thursday.
The campaign has, for the most part, been dominated by the rise in support for Reform UK – and a row over one of the party’s online adverts.
The ad alleged Mr Sarwar would “prioritise” the Pakistani community – but it was quickly branded racist by Labour as it and rivals in the SNP demanded it should be taken down.
Speaking to the PA news agency on Wednesday, First Minister Mr Swinney said he is “confident we have done all that we can” to secure victory for SNP candidate Katy Loudon.
He said: “People face a simple choice in this by-election.
“They can either vote for the SNP – elect an SNP MSP – or they will end up with a Reform MSP. That’s the simple choice.
“People have got to vote SNP to stop (Nigel) Farage and they can vote SNP for the various other steps that we take, our policies on eradicating child poverty, about supporting families in dealing with the cost-of-living crisis.”
He said Mr Farage wants to “undermine the Scottish Parliament” and change the funding formula for devolved services, referring to the Reform UK leader’s comments suggesting the Barnett formula should be “looked at again”.
The by-election is taking place following the death of Scottish Government minister Christina McKelvie, with Mr Swinney saying his party is “working hard to retain the seat in Christina’s memory”.
Earlier, Scottish Labour leader Mr Sarwar said his party had faced a campaign of “misinformation and dirt” from opponents, saying only Labour or the SNP can win the seat.
He posed for pictures with Labour candidate Davy Russell alongside supporters holding up signs saying: “A local champion vs more failure with the SNP.”
Mr Sarwar told PA: “We have focused on the issues that matter here in Hamilton, Larkhall and Stonehouse.
“I think it’s for other parties to explain why they’ve chosen the campaign tactics they have.
“Reform have chosen a campaign of dirt and smear, the SNP have lacked all ambition, the best they can offer is ‘vote SNP to stop Farage’.”
Asked about Mr Farage’s comments earlier in the week, Mr Sarwar said the Reform leader is a “pathetic, poisonous little man”, adding: “Frankly, it’s water off a duck’s back, because I’m fighting to change our country, he wants to divide it.”
Meanwhile, Scottish Liberal Democrat candidate Aisha Mir made a plea to voters to back her.
She said: “For too many people, it feels like nothing works anymore.
“The SNP have failed Scotland for 18 years. The Conservatives are lurching to extremes. Labour are already letting people down. Reform have no real solutions.
“I’m in politics to get things done. I want to be a hard-working local champion who will put your priorities first.”
