When Rishi Sunak walks into the BBC studio this evening to debate Liz Truss, his hopes of becoming prime minister will be on the line.
The former chancellor lies 24 points behind his opponent among Tory members, the very people who will decide who replaces Boris Johnson as party leader and prime minister.
Adding to the pressure on Sunak is the fact that ballot papers will start landing on doormats next week, with many of the 170,000 grassroots activists expected to vote straight away.
That means the MP for Richmond must grasp what opportunities he can in the next few days to start changing members’ minds - starting with this evening’s head-to-head.
The smart money is on tonight’s clash being an even more bloody affair than the last leadership debate on ITV eight days ago.
While Penny Mordaunt, Kemi Badenoch and Tom Tugendhat were still in the race at the time, Sunak and Truss trained most of their fire on one another.
Sunak attacked his rival’s “something for nothing” plans to tax cut, while Truss said his policies would see the UK slip into recession.
The pair also clashed over their backgrounds, with Sunak taking a swipe at Truss’s Lib Dem and Remain-voting past, while she had a pop at his public school background.
With no other candidates to distract them, and Sunak fighting for his political life, tonight’s debate promises to be a no-holds-barred contest.
We got a taste of what’s in store on Saturday when the former chancellor said Truss’s plans to cut tax were “immoral”. Meanwhile, her allies have accused him of being soft on China and weak on illegal immigration.
The biggest loser, however, will be the Conservative Party, as the two contenders to be its next leader try to outdo one another in trashing the government’s record over the 12 years they have been in charge.
Whoever wins will find that re-uniting the Tories will be just as difficult as leading the country.