The benefit was being rolled out for new claimants in Hammersmith, west London, where job-seekers were also required to sign a new commitment setting out what they must do in return for welfare.
Hammersmith is only the fifth area to pilot the new benefit, which was initially intended to cover the whole of the UK by this month.
In 2011, the then welfare minister Chris Grayling told MPs that from October this year, "all new claims for out-of-work support would be treated as claims to universal credit".
But Work and Pensions Secretary Iain Duncan Smith announced in July that just six Jobcentres, including Hammersmith, would begin taking Universal Credit claims "starting from October".
The director general of Universal Credit Howard Shiplee said last month that these six would join the scheme between October 2013 and the spring of 2014, and the Department for Work and Pensions says it aims to begin taking claims in Rugby, Inverness, Harrogate, Bath and Shotton in North Wales "by the spring".
Universal Credit will roll six out-of-work benefits - income-based Jobseeker's Allowance, income-related Employment and Support Allowance, Income Support, Child Tax Credits, Working Tax Credits and Housing Benefit - into one, with the aim of ensuring that claimants are always better-off taking work.
Initially being introduced for new claimants, Mr Duncan Smith aims to move all existing jobseekers on to the new benefit by 2017.
But the flagship scheme has been plagued by IT problems.
A scathing report by the National Audit Office last month criticised ''weak management, ineffective control and poor governance'' and revealed that £34 million had been wasted on failed IT. Former Olympics executive Mr Shiplee was drafted in earlier this year to ''reset'' the programme.
Welfare reform minister Lord Freud said that the roll-out of Universal Credit in Hammersmith reflected the success of the Government's "slow, safe and controlled" approach to what has been described as the biggest ever shake-up of the welfare state.
"Universal Credit is modern welfare that rewards people who move into work, supports those who've fallen on hard times and is fair to taxpayers," said Lord Freud.
"We introduced Universal Credit in a slow, safe and controlled way in Manchester and this careful approach is working well. Most people are claiming it online, the IT is working and comprehensive support is in place. We will build on these successes as Universal Credit rolls out across the country."
Hammersmith Jobcentre will also start trialling intensive support for new jobseekers, giving claimants four face-to-face interviews with "work coaches" within the first two weeks of their claim.
They will also be required to sign the new Claimant Commitment, which sets out what jobseekers must do in order to receive state support and provides information about the consequences of failing to meet requirements.
The commitment is being introduced in 100 Jobcentres a month and is due to be fully in place across the country in the spring of 2014.