Liz Truss tonight set her sights on the Welsh First Minister - just days after saying she would "ignore" his counterpart in Scotland.
Ms Truss, who is the favourite to succeed Boris Johnson, dismissed Labour's Mark Drakeford as a "low energy Jeremy Corbyn" and told the party faithful: "I will crack down on his negativity."
The Foreign Secretary looks set to have a difficult relationship with devolved governments, having described Nicola Sturgeon as an "attention seeker" earlier this week.
She doubled down on her attack on Ms Sturgeon tonight, stating: "The entire resources of the Scottish government is being used to run an independence campaign.
"They're not delivering for the people of Scotland, Nicola Sturgeon is spending her time advocating for an independent Scotland."
She made the comments at a hustings event in Cardiff, where rival Rishi Sunak said he was "glad" she had performed a U-turn on catastrophic plans that would have seen hundreds of thousands of public servants endure a pay cut.
Protesters had earlier gathered outside the event holding placards making their opposition to the party known.
"Never Truss a Tory," one sign proclaimed. "They'll screw you over Sunak or later," said another.
The candidates spelled out their priorities to a room full of Tory members in the Welsh capital - one of 12 hustings events being held for party loyalists around the UK. The next Prime Minister will be picked by an estimated 160,000 Tory members - around 0.3% of the UK population.
Asked about Ms Truss' screeching U-turn over public sector pay, Mr Sunak said: "I don't think cutting the pay of hundreds of thousands of workers here is a Conservative policy we should adopt and I'm glad she's changed her mind."
Despite the damaging debacle he said he would have no hesitation in offering his rival a place in the cabinet if he were to win.
Ms Truss continued to maintain that her policy - which her team claimed would save £8.8 billion - was "misinterpreted", but added: "This isn't part of my central costings."
She claimed that nurses, doctors and teachers would not have been affected by her controversial regional pay boards plan - but said: "I've been very clear that I'm not going ahead with this policy."
She did not elaborate on how she felt the policy had been misinterpreted, or why she did not clarify it rather than scrapping it altogether.
Elsewhere she pledged to extend the controversial Rwanda deportation policy to "more countries", and said she would focus on “getting rid of all EU laws” by the end of next year.
Former Tory leader Lord Michael Howard, who is backing Mr Sunak, told the party faithful: "We will only win the election if inflation is under control, borrowing is under control, interest rates are coming down and our economy is on the path to recovery.
" Rishi Sunak is the only candidate whose policies can deliver that outcome."
Mr Sunak - referencing the number of Welsh party stalwarts named Davies - awkwardly quipped: "If I just became Rishi Davies maybe I'd have the edge in Wales."
Ms Truss, who followed him to the podium, enthused about learning to shear a sheep in Wales.
Challenged by an audience member over the rise in pension ages for 3.8 million women under the 1995 Pension Act, Mr Sunak said: "I'm going to be straight with you, I can't promise that I will resolve that situation... I know that's not the answer that you want, but I must be honest with you."
The response was met by silence in the room.
An hour before the hustings began, Ms Truss was boosted when Tory heavyweight Sajid Javid announced he was supporting her bid for No 10.
Mr Javid, who had kept his cards close to his chest after his own leadership campaign came crashing down, warned that Rishi Sunak's policies would lead Britain “sleepwalking" into a high-tax, low-growth economy.
The former cabinet member - who has served as Chancellor of the Exchequer, Home Secretary, and Health Secretary - this evening said he was backing Ms Truss to be the next PM, The Times reports.
He is the latest big name within the party to voice his support for the Foreign Secretary in recent days, following Penny Mordaunt and Ben Wallace.
By supporting Ms Truss, he has sided with the overwhelming favourite in the leadership race.
A ConservativeHome website poll of 1,003 activists found 58% plan to vote for Ms Truss and 26% for Mr Sunak, with the rest undecided.
A spokesman for Ms Truss’s campaign said: “Tonight’s poll shows Liz’s vision for the UK is resonating with members.
“They believe in her bold and ambitious economic plan for the country, they know she’s on the side of people who work hard and do the right thing and they trust her to deliver on the opportunities of Brexit.
“We are not complacent, and Liz will continue to hustle for every vote over the coming weeks.”
