Labour Party leader Ed Miliband did much to boost his credibility as a potential prime minister in interviews broadcast by Sky News Thursday night.

By contrast, David Cameron, the incumbent, seemed caught off guard by presenter Jeremy Paxman’s grilling. He was forced to admit that his party had failed to keep its promise to bring down the national debt and only conceded after being asked several times that he would not be able to live off a zero-hours contract either.

The number of Britons on zero-hours contracts has risen 100,000 in the last year alone, now representing 2.3 percent of the workforce. The expansion in zero-hours contracts has helped bring down unemployment from 8 percent when Cameron took power in 2010 to 5.7 percent last month. A record number of Britons is now in work but almost 700,000 lack job security.

Cameron “never recovered from these missteps and rarely appeared in control,” wrote New Statesman‘s George Eaton.

The Telegraph‘s Dan Hodges agreed, writing it was “the weakest public performance I’ve seen from him since he became prime minister.”

Paxman was tough on both candidates but Miliband had the advantage of taking questions from the audience first. He appeared unusually confident during this Q&A session, recognizing that the last Labour government had failed to properly regulate the banks as well as immigration before making the case that Britain could “do better.”

“I think this country’s too unequal and we’ve got to change,” Miliband said.

Sky News’ political editor, Faisal Islam, said the performance was surprising. “We saw a kind of hard Ed Miliband that you would not recognize from the papers.”

The Labour leader is often criticized for appearing feeble. He told Paxman he didn’t care if voters thought he was a “north London geek” and that his opposition to what would have been an American-led military intervention in Syria in 2013 proved he was “tough enough” to lead the country.

Standing up to the leader of the free world, I think, shows a certain toughness.

Attacking Barack Obama might not have been the best way to convince leftwingers of his toughness and conflating potential airstrikes in Syria with the 2003 invasion of Iraq was unfair. But it was the first time in a long time that Britons saw Miliband so sure of himself.

Cameron did well in answering questions from the audience too. He evaded only one — on his broken promise not to impose a “top-down reorganization” on the National Health Service. He pointed out instead that the Conservatives had kept their word not to cut health spending and voiced cautious support for further liberalization.

It was “very smooth,” said Islam; “the prime minister that we know, involving anecdotes about his family, sounding very ordinary and normal. It was his comfort zone.”

It did not make up for his earlier lackluster performance, though. As The Telegraph‘s James Kirkup argued, “what really counts is expectations, how you perform relative to what people expect of you.” In that sense, Miliband won. He “entered the room with a reputation for being a hopeless ditherer but failed to live up to it,” according to Kirkup, “by being warmer and more assertive than many watching would have expected.”

Cameron had refused to debate Miliband directly, saying all party leaders should be invited. Two debates, one hosted by ITV and another by the BBC, will be aired in April involving the leaders from other major parties as well. Elections are due May 7.