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."