It was a confident, well-measured and sure-footed performance.
Quick wins, even if they buoy up your MPs, sometimes don’t stand the test of time or events.
Almost inevitably, the mood was flatter than when the great showman Boris Johnson was at the Despatch Box until his premiership was toppled by a ministers’ mutiny after just three years dogged by controversies.
Sir Keir was quick to put Ms Truss on the spot over another windfall tax on oil and gas giants raking it in as energy prices have soared following Vladimir Putin’s invasion of Ukraine.
“I’m against a windfall tax. I believe it is the wrong thing to be putting companies off investing in the United Kingdom just when we need to be growing the economy,” she declared.
Sir Keir responded: “I ask because the Treasury estimates are that the energy producers will make £170 billion in excess profits over the next two years.
“The Prime Minister knows that she has no choice but to back an energy price freeze but it won’t be cheap and the real choice, the political choice, is who is going to pay.
“Is she really telling us that she is going to leave these vast excess profits on the table and make working people foot the bill for decades to come?”
Ms Truss, who has laid out a tax-cutting agenda alongside an energy package which could top £100 billion, was defiant.
“I understand that people across our country are struggling with the cost-of-living and with their energy bills,” she said.
“And that is why I as Prime Minister will take immediate action to help people with the cost of their energy bills and I will be making an announcement to this House on that tomorrow, giving people certainty to make sure that they are able to get through this winter.
“But we can’t just deal with today’s problem. We can’t just put a sticking plaster on it. What we need to do is increase our energy supplies long-term and that is why we will open up more supply in the North Sea which the Honourable Gentleman has opposed, that is why we will build more nuclear power stations, which the Labour Party did not do when they were in office.”
Sir Keir doubled down on his attack, accusing Ms Truss of seeking to protect the profits of oil giants like Shell and give companies such as Amazon a tax break, through ditching the planned increase in Corporation Tax from 19 per cent to 25 per cent next year, rather than helping families and public services.
He added in the Commons: “She’s the fourth Tory Prime Minister in six years - the face at the top may change but the story remains the same.
“There’s nothing new about the Tory fantasy of trickle-down economics, nothing new about this Tory Prime Minister who nodded through every decision that got us into this mess and now says how terrible it is, and can’t she see there’s nothing new about a Tory Prime Minister who when asked who pays says ‘it’s you, the working people of Britain’?”
Ms Truss, though, then struck her first blow which delighted Tory MPs.
“There’s nothing new about a Labour leader who is calling for more tax rises,” she hit back.
“It’s the same old, same old tax and spend. What I’m about is about reducing taxes, getting our economy growing, getting investment, getting new jobs for people right across the country.
“I’m afraid (Sir Keir) doesn’t understand aspiration, he doesn’t understand opportunity, he doesn’t understand that people want to keep more of their own money and that is what I will deliver as Prime Minister.”
Cricket fan Theresa May then threw Ms Truss a half-volley outside off stump, by asking why all three female prime ministers had been Conservative.
“It is quite extraordinary isn’t it, that there doesn’t seem to be the ability in the Labour party to find a female leader or indeed a leader who doesn’t come from north London,” said the Prime Minister to another wave of cheering, and possibly relief, from Tory MPs.
As she headed back to No10, Ms Truss could reflect on a solid performance at her first PMQs, certainly better than Sir Keir’s start as Labour leader, and she will no doubt get stronger the longer she is in office.
But she has firmly nailed her colours to the mast of no new windfall tax on energy giants which is likely to become an increasingly difficult position to defend in the cold and dark winter months ahead as many households struggle to afford their bills.
And she certainly gave the impression, as they say, that this lady is not for turning.
So, what is increasingly clear is there is now a far bigger divide between the Conservatives and Labour on economic policy, for the public to choose between at the next General Election.