Plaid Cymru: Wood cannot become first minister says rival Price
Leanne Wood cannot become first minister, Plaid Cymru leadership candidate Adam Price has said.
In his first interview since announcing his bid, Mr Price said Plaid will lose the next Senedd election if it carries on the current track.
He said he can "create the momentum" the party needs.
Mr Price, AM for Carmarthen East and Dinefwr, is competing against Ynys Mon AM Rhun ap Iorwerth and Rhondda's Ms Wood for the post.
Asked if he did not believe Leanne Wood could become first minister, he told BBC Wales: "We are at a cross roads as a party.
"If we continue on the current track then we will lose the next election, and that will be a tragedy.
"There's a brief window of opportunity for us. The Labour party that has been a massive dominate force in Welsh politics is going to be vulnerable at the next election.
"In Mark Drakeford, a nice and very able man, he an hardly represent himself as a force for change in the country that is crying out for it".
Mr Price said he can "create the momentum that we need to get people believing again that this country can be different".
"We need a great transformation in Wales. Plaid needs to be the vehicle for that," he said.
Mr Price and Mr ap Iorwerth triggered a leadership contest earlier in July.
Prior to the announcement of his bid, Mr Price criticised what he described as Plaid's "plodding politics of the parsimonious press release, the tired tweet and the formulaic Facebook status".
He told BBC Wales: "There is an appetite out there for the kind of dynamic, great transformation that I want to see.
"Unfortunately we've not been able to tap into that.
"If we just continue the one more heave school of politics, just continue on the same track, woe betide us if we then find we get the same result in 2021.
"If we want to be the change in Wales we first have to show we can change ourselves.
"We have to convince people that we have the appetite, the hunger, the ambition to be the next government in Wales.
"I have that ambition. It was a difficult decision for me to make but now I'm determined to do it.
"We can win and we can restore the faith in the democracy of this country."
Mr Price said the pro-devolution party has "adapted least to the pro-devolution environment".
"We've been historically a party of protest, which is essentially pointing out the horrible things done to Wales by London governments.
"But you know what, the conversation we need to be having is about our own government - and we haven't made that mental shift."
Asked if he's the thinker in the party, he said: "I certainly wouldn't take that as an insult".
And pressed on whether he was confident of winning, he added: "I have to."
Analysis by Aled ap Dafydd, BBC Wales political correspondent
Adam Price has been a member of Plaid Cymru since he was 13.
Days before the result is announced he'll reach the significant milestone of 50.
That's nearly 40 years to live and breath everything the party has done and crucially hasn't achieved.
Publicly he's the effervescent face of Plaid, always talking up electoral fortunes and sending the troops home happy at the end of conferences.
Privately Adam Price has aired concerns about the party's fortunes.
A failure to articulate what a change of government would mean is his primary criticism. Most damning of all is his view that for 20 years Plaid hasn't understood the requirements of devolution.
In the next two months a man who's never shy of an idea will be in overdrive.
Central to his campaign will be the word "change" - saying it loudly and often in a leadership battle could be enough to secure victory.
Changing the colour of government is another matter.
The son of a miner who went to Harvard has already proved an ability to change the natural course set out for many of his peers. Here comes the latest test.