Speaking after Mr Juncker's damning assessment, Theresa May's spokeswoman said Britain felt it was in a "good position" in the talks and wanted to agree to move on to discussions about its future relationship by the current deadline of October.
The EU has said that talks can not move on to discuss broader issues until it is satisfied enough progress has been made on three key points; citizens' rights, the Irish border and the "divorce bill".
Britain says the two strands should be negotiated in parallel, arguing that progress on a free trade deal may even help resolve other sticky issues such as the future EU-UK border between Northern Ireland and the Republic.
Labour, the British opposition party, wants to keep Great Britain in the European single market during a transition period after Brexit should they come to power.
Remaining in the Customs Union and Single Market would mean the nation would continue to accept the jurisdiction of the European Court of Justice (ECJ) on trade issues, pay money to Brussels, and abide by the bloc's "Four Freedoms" - significantly, the associated uncontrolled, unvetted Free Movement of people until 2023.
Mr Barnier added: "To be honest, I'm concerned, time passes quickly".
However, Mr Davis appeared to issue a rebuttal on Monday as he pointed to the seven new Brexit-themed papers published by his department over the last fortnight as proof of the "hard work and detailed thinking that has been going on behind the scenes".
David Davies dismissed criticism, calling on Brussels to show "flexibility and imagination" in the negotiations, insisting that "technical discussions" must move forward on a range of issues.
There are three main issues that the United Kingdom is going to be expected to make progress on before talks can focus on trade, according to a unanimous decision by European leaders: the exit bill, the Irish border, and the rights of EU citizens in the United Kingdom and British people in Europe after the separation takes place.
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Although Neymar did not add to his three goals , his free kick led to PSG's second goal, which was scored by midfielder Thiago Motta. "However, we had better control in the second half, but this was a hard match, so the three points are important".
"In order to do that, we'll require flexibility and imagination from both sides", he said.
Ahead of the talks, Mr Davis was believed to be frustrated at Mr Barnier's insistence that progress must be made on fixing the UK's "divorce" bill before moving on to talks on future trade.
He was welcoming UK Brexit Secretary David Davis to Brussels for their third round of monthly face-to-face talks which was already fraught with frustration on both sides.
Britain voted to leave the European Union in a referendum last year and Prime Minister Theresa May issued a formal notification in March, starting a two-year negotiating timetable to exit.
Senior EU officials have said this is not just an economic issue - it is also a societal and therefore a political issue.
'So there is still an enormous amount of issues which remain to be settled.
Slovenia's Prime Minister Miro Cerar last week warned that the process will "definitely" take more time than expected.