The president tweeted: "Oil prices getting lower. Great! Like a big Tax Cut for America and the World. Enjoy! $54, was just $82. Thank you to Saudi Arabia, but let’s go lower!"
He followed up moments later by repeating his slogan, "MAKE AMERICA GREAT AGAIN!".
Mr Trump's statement strains credibility. Most oil analysts credit Russia for pressuring Saudi Arabia and other oil-producing nations to keep output up and oil prices down.
Mr Trump himself also played a role. By granting waivers from U.S. sanctions on Iran oil sales to China, Japan, and six other countries, he undermined expectations of a crunch and created an unanticipated glut in the market, collapsing oil prices.
The president likely hopes news about oil prices will divert attention away from his handling of the Khashoggi affair. The Washington Post columnist was ambushed, murdered, and dismembered by a Saudi kill team in Istanbul 50 days ago. Despite global outrage over the killing of the journalist, Mr Trump has insisted on sno erious consequences for the Saudi leadership believed to have ordered the assassination because of Saudi weapons purchases, the White House's confrontation with Iran, and oil prices.
Lower oil prices might please US consumers, but will likely not help Mr Trump politically. Despite a booming economy, Mr Trump's approval ratings remain low, with 53 per cent of voters disapproving of his presidency.