If the election had gone as expected, Davis would have been armed with a stronger mandate and negotiating hand than when Theresa May first became Prime Minister in July 2016.
It's a position that is likely to limit her flexibility during talks.
After nearly a year of waffling, Britain on Monday finally opens negotiations with its European Union counterparts about leaving the bloc, with the final outcome, due in 2019, as important as it now seems unpredictable. May, whose future is uncertain after she lost her Conservative majority in an election this month, has insisted that trade talks start immediately and run in parallel.While Barnier insists on the "sequencing" of talks, so that trade negotiations can not start until probably January, finding a way to avoid a "hard" customs border for troubled Northern Ireland may well involve some earlier discussion of the matter.
Austrian Foreign Minister Sebastian Kurz says: "If we don't succeed both sides will lose". Dozens of officials supported Mr Barnier and Mr Davis as they met in broad sessions and one-on-one meetings.
Officials on both sides play down expectations for what can be achieved in one day.
Responding to Mr Barnier, Mr Davis quoted wartime British prime minister Winston Churchill: "No doubt the road ahead will at times be challenging, but as Churchill once said, a pessimist sees the difficulty in every opportunity".
The center-left Social Democrat strongly criticized May's Conservatives, saying that they "played with the emotions of citizens in Britain, told fake news about Europe and left people unclear about what consequences this would all have".
"I can't say whether there is a chance of that happening", Gabriel said Monday at a meeting of European Union foreign ministers.
Britain's Boris Johnson said that he looked forward to "a happy revolution" in relations that would be good for Britain and the rest of Europe, pointing out that the most important thing for both sides is to think about their new partnership, the deep and special partnership that the United Kingdom wants to build with their friends.
Under the Article 50 process, Britain must leave the European Union unless the other European Union states unanimously agree to extend the deadline.
Chancellor Philip Hammond has dismissed speculation that he will push for a soft Brexit by arguing for Britain to remain in the customs union and single market.
Other issues that have to be sorted include the status of the border between Northern Ireland and the Irish Republic.
Barnier, a veteran French politician, has been vested by the European Union's 27 remaining countries to enforce their no-compromise red-lines that any deal for Britain must not be more favorable than the one it now has as a full member.
Davis said she will tell them about plans to guarantee rights for some 3 million European Union citizens in Britain under a proposal to be made next week.
In any event, the two sides reached no farther than the foothills of their climb.
The UK could fall back on World Trading Organisation default tariffs under a hard-Brexit "no deal", making multi-national firms' exports more expensive to buyers in the bloc.
Last month, Mr Davis vowed to wage the "row of the summer" to secure immediate talks on a free trade agreement - predicting an early collapse if the European Union refused to give way. The EU insists that should wait until an outline agreement on divorce terms, ideally by the end of this year.