Peter Mandelson has promised to be a "dedicated team player" as new EU trade commissioner and says he has moved on from daily support for Tony Blair.
Mr Mandelson's performance impressed many observers
In a grilling from MEPs, Mr Mandelson stressed his desire to revitalise Europe's economic dynamism.
Making the case for fair trade, the former Cabinet minister said poor countries needed special deals.
His performance on Monday won him the endorsement of most of the European Parliament's trade committee.
BBC correspondent Emma Jane Kirby said Mr Mandelson began the three-hour session by speaking in French with a strong English accent but was given permission to switch to English.
She said Mr Mandelson's position facing the panel gave him no doubts this was not an informal round table discussion but a determined grilling and she said he was "bombarded" with questions.
'Britain's place is in Europe'
He told MEPs: "I do not share the half-in, half-out attitude to the EU of some in Britain. Britain's place is in Europe."
The Greens and United Left voiced reservations after the hearing.
Mr Mandelson is due to take up his job on 1 November, but his appointment still depends on a vote of the full European Parliament later this month on whether to accept the new commission en-bloc.
But he also pledged to try to improve Europe's trading relations with the United States.
"We should find new ways to move forward by reducing the scope for conflict between our regulatory approaches and by forging closer cooperation," he said.
He argued there had to be moves to ensure world trade worked in a way which reversed "gross inequalities and desperate poverty" in developing countries.
"I certainly believe that we gain through open trade and liberalisation. But
for me liberalisation is not an end in itself. It is a means for creating a
better and more just society and improving people's lives," he said.
Mr Mandelson stressed the importance of the continuing world trade talks, saying he hoped the current round of talks could be completed during 2006.
He outlined two key challenges facing the EU - revitalising economic dynamism and helping Europe become an effective "force for good" as the best way of achieving security.
"Where people are given hope, they will be less willing to take up the weapons of hopelessness," he said.
British MEPs say they want assurances Mr Mandelson, a close ally of Tony Blair, will be his own man.
Mr Mandelson said he would continue to be a friend of Mr Blair but his chief allegiance would be to commission president Jose Manuel Durao Barroso.
"I have moved on from being a British parliamentarian, I have moved on from being a New Labour politician, I have moved on from being the supporter in the active day-to-day sense of Tony Blair," he said.
The job of commissioners is to act in the general European interest, not to advance the interests of their own country.
Our correspondent said he did not lose his temper even when Nigel Farage, a UKIP MEP, pleaded with him to come to the UK and campaign for a Yes vote for the European constitution, saying it would help UKIP's cause.
Mr Mandelson said he would indeed be campaigning for a Yes vote and, he retaliated to the Eurosceptic MEP by pointing out the word sceptic actually means "open to persuasion".