Amid reports he has asked advisers if he is allowed to fire the chair of the Federal Reserve, Donald Trump tweeted on Monday that the central bank is “the only problem our economy has” because, in part, it does not “understand necessary trade wars”.

Inimitably, the president also likened the Fed to “a powerful golfer who can’t score. He can’t putt!”

On Sunday, after stock markets suffered their worst week in a decade, the treasury secretary, Steve Mnuchin, revealed he had spoken to the heads of six major banks and convened the working group on financial markets, a presidential advisory panel known colloquially as the “plunge protection team”. Digesting that news on Monday, markets failed to rally.

Trump’s reported musings about firing Jerome Powell, his own appointee who has raised interest rates against the president’s wishes, have stoked Wall Street jitters. So have the president’s tariffs-based trade war with China, the government shutdown and the resignation of Jim Mattis, the respected secretary of defense.

Over the weekend, Mnuchin and the acting chief of staff, Mick Mulvaney, attempted to dowse controversy over Trump’s urge to get rid of Powell, which he is thought to be unable to do, the Fed being by design independent.

Mnuchin issued a statement in which Trump denied he had ever asked the question, a position Mulvaney seemed to undermine by saying the president “now” understood he could not make such a move.

Undaunted, and following bilious tweets about Mattis and the diplomat Brett McGurk that indicated a lack of Christmas cheer at the White House, Trump returned to the subject.

“The only problem our economy has is the Fed,” he wrote. “They don’t have a feel for the Market, they don’t understand necessary Trade Wars or Strong Dollars or even Democrat Shutdowns over Borders.”

Trump then reached for a trusted club with which to beat an opponent.

“The Fed is like a powerful golfer who can’t score because he has no touch,” he wrote. “He can’t putt!”

Though he famously chided Barack Obama for spending too much time on the fairways, Trump spends many weekends at his properties up and down the east coast, driving, chipping and putting, sometimes using a companionable 18 holes to spend time with aides, allies or foreign leaders. The cost to the taxpayer has become a contentious subject.

According to the Washington Post, in his spare time Powell “plays golf and the guitar”. That profile did not mention his handicap, but it did add that the Fed chair “doesn’t drink much” – a point of similarity with the teetotal Trump – and “has an odd ability to repeat people’s sentences backward to them, a quirk former colleagues say is a reminder of his smarts – and how closely he listens”.

It was not immediately clear if Powell had read Trump’s Monday tweet, let alone read it to him backwards.