Mr Sunak and Ms Truss clashed most ferociously over their Brexit record and their plans for taxation in the UK as they addressed the audience in Hanley's Victoria Hall.
Appearing after the two were selected as the final two candidates by Tory MPs, they attempted to sway voters who backed Prime Minister Boris Johnson in the last election that their path was the right way forward.
Ms Truss was particularly vocal in her criticism of the former Chancellor's taxation plans, saying his policies will crash the economy and that his emphasis on paying back debt is a "massive mistake".
The Foreign Secretary said during the BBC debate: “I would obviously make sure, my Chancellor would make sure that we optimise the way we are taking out those debts.
“The point I am making is, I am illustrating the fact that when you have a major world event, a major economic shock, trying to pay back the debt as quickly as possible is not the right thing to do economically.
“We didn’t do that after World War 2. We shouldn’t do that now.
"And crashing the economy in order to pay a debt back quicker is a massive mistake.”
Rishi Sunak and Liz Truss before taking part in the Tory leadership debate, based in Stoke-on-Trent Jacob King
Former Chancellor addresses the Stoke-on-Trent crowd Jacob King
Interjecting, Mr Sunak told the Victoria Hall crowd: “The mistake that we will make is that at a time when inflation is already high, everyone’s already feeling it in their belt, interest rates are already on the rise, so, into that situation does anyone think that the sensible thing to do is go on a massive borrowing spree worth tens of billions of pounds and fuel inflation?”
The former Chancellor said that “if we do, inflation stays here for longer and interest rates are going to go up”.
In response, Ms Truss accused him of fearmongering.
Brexit was also an issue that provoked a strong reaction from the two candidates.
Mr Sunak reminded the Stoke-on-Trent audience that "only one of us was on the Leave campaign" – a particularly potent point given Stoke voted strongly in favour of pulling out of the EU in 2016.
To this, Ms Truss insisted she has changed her mind and is committed to making Brexit a success.