What should have been a joyous coronation felt bizarrely flat, with Ms Truss waiting for applause so intently there was an almost nervous laughter in the room.
Things had been set up for this, most notably by the Tory chairman opening, who told the assembled MPs, staff and media the Conservatives had shown the best of the Tory party.
Then there was her winner’s speech itself, which despite only lasting minutes still prompted one Tory MP to proclaim within earshot “we’re totally f****d”.
The only real topic that seemed to cheer the room was the mention of Boris Johnson, whose very name garnered applause longer than Ms Truss’s speech.
She praised him for being loved from “Kyiv to Carlisle”, before pausing for what felt like a lifetime for applause.
That she drew the line before the Scottish border did not go unnoticed in the room.
Then there was the promise of winning an election in 2024, seemingly ruling out a general election.
With polling showing her as leader putting the Tories 17 points behind the Labour party, it seemed a wise move.
Speaking to supportive MPs after, the mood was less one of hope than expectation.
One praised her campaign, but added it would be hard to judge her until she showed her plan for the economy and cost-of-living crisis.
That we still don’t know speaks to the problems facing the Tories. Ms Truss will need to act soon to avoid being simply a footnote Prime Minister.