
Global financial markets went into a tailspin after partial election results increasingly pointed to a shock win by billionaire Trump.
At around 0615 GMT, US benchmark West Texas Intermediate for delivery in December was down $1.22 at $43.76 and Brent crude for January tumbled $1.08 to $44.96 a barrel.
"This is very much a step into the unknown because we simply can't know what type of president Trump will be," research firm Capital Economics said in a note.
"Will he be the demagogue from the campaign trail, who threatened to lock up his political opponents, punish the media, build border walls and start a global trade war?" it said.
"Or is he capable of becoming a statesmanlike figure who leads in a more measured manner?"
Jeffrey Halley, a senior market analyst at OANDA, told AFP oil will be under pressure as it is not a safe-haven asset like gold, whose price has risen.
"I guess we're going to see continued sell-off in commodities and oil is one of them," he said.