Key Points:

Helen Clark clearly dominated the Leaders' Debate on Tuesday night. She had all her arguments at her fingertips and, from the start, bulldozed right over the top of John Key. It is easy to see how she crushed her National opponents in previous election campaigns.

But she has met a harder adversary in Key, who could hold his own most of the time. But where he had the edge was in coming over better on television. Clark was very much the prime minister, talking knowledgeably and forcefully around big issues. Key, however, was able to couch his talking points in a way that resonated better with viewers. In short, Key connected.

The unscientific phone-in poll at the end of the night showed two out of three viewers favoured Key. Labour's spin the next day that their supporters didn't have cellphones or the money to text was rather lame.

The debate wasn't about Clark, her government or even policy. What most people sat down to watch was whether Key was competent enough to do the job of prime minister.

Key is still an unknown entity to most of us. The only time we have seen Key in action is in one-on-one interviews, most of them puff pieces, and media soundbites.

This is the first time most of us have seen Key in a prolonged setting where he was tested, in this case by the prime pinister. Because of the world economic crisis, people won't move away from Clark unless they are sure Key can do the job. Frankly, it was a job interview.

Unfortunately for Clark, she was always going to lose the debate if Key did even moderately well - it was assumed she would perform well.

Clark's opening address let her down because she didn't define the debate. She should have rammed home the world economic crisis and said we couldn't afford to hand over the government to someone inexperienced, backed up with a front bench of failed political hacks from the Shipley era. Her best chance of winning this election is to reinforce her message about experience and competency over Key's inexperience and his party's incompetence.

In the economic and tax discussions, Clark had Key on the back foot. Key looked uncomfortable when he had to explain his tax cuts and had no response to arguments he was using KiwiSaver to fund them.

It would have been a surprise to most viewers that in some cases Labour's tax cuts were better than National's. No wonder National has gone quiet on its tax cuts.

Clark was able to neutralise the discussions about crime, where Key would have been expected to win. But Key did trip Clark up during the environmental discussion. Few of us would have known that we are one of the worst polluters per capita in the world and are getting worse.

But the leaders got in good points because the questions were fairly predictable and they had notes.

I think the real benefit to voters was the response to personal questions the leaders weren't expecting. Clark was clearly embarrassed about being asked whether she felt rich. Her response that she didn't really think about the money would have upset people who struggle to meet their next bill. Key's answer was a master stroke, turning around the question about his wealth into empathising with people who struggle to make ends meet.

Clark also reacted defensively when Key slipped in the clever dig about Labour restricting the amount of water we can use in the shower. Key's accusation wasn't true, but Clark's rattled reaction showed it was a big hit. Key's shower nozzle quip would have reminded people about Clark's controlling "nanny state".

But then Key was on the end of a couple of major hits. His denial he'd said in a private conversation with Maori Party leader Pita Sharples that National wouldn't abolish the Maori seats had him on the ropes.

He had the same look as when he got caught out telling porkies over his Tranz Rail shares. This reinforces Labour's accusation Key is not averse to fibs when it suits.

His admission afterwards he had made those comments to Sharples should get him off the hook for now. But it does raise a question in people's minds about his honesty.

The other issue was Key's stance on the Springbok Tour 27 years ago. His answer that he didn't really have an opinion at the time was revealing.

For those of us who were teenagers or older, the tour was a defining moment in our political consciousness.

For a person aspiring to be prime minister not knowing what he thought about that issue reinforces Labour's charge that Key has no political values but is just an ambitious, ex-money speculator on the make.

Voters do seem to want a change. But Clark and this government are not unpopular.

For most people, the question is: if they take the risk, can Key do the job? On Tuesday night, despite Clark landing a few blows, he came across as decent and competent. More importantly, he connected with the viewers.

That makes Clark's job a little harder than it was last week.