Liberal Democrat leader Nick Clegg has told party workers thay are "here to win" the crucial Oldham East and Saddleworth by-election.
The Deputy Prime Minister mingled with supermarket shoppers in the aisles as he paid his second visit to the constituency ahead of next week's vote.
Lib Dem candidate Elwyn Watkins was just 103 votes short of unseating Labour's Phil Woolas at the General Election last May, making the constituency one of Mr Clegg's top targets.
Mr Clegg is hoping his party will benefit from voter distaste for Labour due to Mr Woolas's removal as MP by the courts because of misleading leaflets he put out during the General Election campaign.
He dropped into Asda supermarket in Shaw and emphasised that no deal had been struck with his coalition partners, the Conservatives, after suspicions that Prime Minister David Cameron would secretly hope for a Lib Dem victory.
On his arrival, a handful of protesters - believed to be students - pushed their way through Lib Dem supporters holding placards as Mr Clegg approached the supermarket entrance.
One young woman was bundled away quickly by security staff as she waved a home-made banner directly behind the deputy prime minister.
The by-election is being seen as the first major test of how the Conservatives and Lib Dems campaign against each other, while working together in coalition.
The Prime Minister is expected to make an appearance in the constituency this week, while Labour leader Ed Miliband visited Oldham on Monday to support candidate Debbie Abrahams and denounce Tuesday's VAT hike.
UKIP leader Nigel Farage and BNP leader Nick Griffin have also been campaigning in the constituency on behalf of their chosen candidates this week.
The full list of candidates (in alphabetical order) is:
Debbie Abrahams (Labour)
Derek Adams (British National Party)
Kashif Ali (Conservative)
Peter Allen (Green Party)
David Bishop (Bus-Pass Elvis Party)
The Flying Brick (Monster Raving Loony Party)
Loz Kaye (Pirate Party of the United Kingdom)
Stephen Morris (English Democrats)
Paul Nuttall MEP (UK Independence Party)
Elwyn Watkins (Liberal Democrats)