The chancellor has described as "bizarre" and "absurd" accusations he is talking down the economy.
Philip Hammond had been criticised for saying that the Brexit process has created uncertainty.
But in an interview, Mr Hammond said he was a realist and that he wanted to "protect and prepare" the economy for the challenges ahead.
Mr Hammond was speaking in Washington, where he is attending an International Monetary Fund meeting.
The chancellor said:"It is absurd to pretend that the process we are engaged in hasn't created some uncertainty.But the underlying economy remains robust.
"I am committed to delivering a Brexit deal that works for Britain," he added.
He refused to answer how he would vote if another referendum was held now."We've had the referendum," he said."You know how I voted in it."
Mr Hammond is due to comment further in a BBC interview later on Friday.
This week former Conservative Chancellor Nigel Lawson called for Mr Hammond to be sacked, saying he was unhelpful to the Brexit process.
The chancellor, who has been accused of being too pessimistic about Brexit, this week told the Treasury Committee of MPs that a "cloud of uncertainty" over the outcome of negotiations was "acting as a dampener" on the economy.
Mr Hammond said the government would not spend taxpayers' money preparing for a "no-deal" Brexit until the "very last moment".
He said he wouldn't take money from budgets for other areas such as health or education just to "send a message" to the EU.
One former minister, David Jones, has said billions of pounds should be set aside in November's Budget for a "no deal" scenario.
He argued that if this did not happen it would be seen as a "a sign of weakness" by EU leaders who would think the UK was not serious about leaving the EU without a deal....