After setting a new championship record at the European Championships in Birmingham, Sweden's double Olympic gold medallist Duplantis soared 6.20m to add another title to his illustrious resume.
"I was a little scared before the competition because I didn't know if my body would hold up," Duplantis told reporters after the event, referencing the injury trouble he suffered earlier this season. "It feels so good and I'm overjoyed. I feel maybe happier than ever."
Duplantis secured first place after his great rival Emmanouil Karalis of Greece failed to clear 6.25m, having gone clear at his first attempt at 6.15m.
The prize pot of $10 million is the richest in athletics, with winners pocketing $150,000. Runners-up win $75,000, with $40,000 awarded for third. The victorious relay teams split a pot of $80,000.
Olympic champion Ingebrigtsen won with a late surge in the 5000m, clocking 12 minutes 59.24 seconds just seven months after undergoing Achilles surgery. Mahuchikh soared 1.99m to win the women's high jump.
Germany's Merlin Hummel won the hammer throw with 81.46 metres. Olympic champion Ethan Katzberg was stung by the rule, unique to this event, that guarantees athletes only two throws in a first round. The Canadian fouled on both of his attempts.
American world record-holders won both sprint hurdles events with Masai Russell taking the 100m hurdles title in 12.22, and Ja'Kobe Tharp clocking 12.94 to win the men's 110m hurdles title. The United States edged Jamaica by 0.08 seconds to win the mixed 4x100m relay.
Larissa Iapichino of Italy leapt 6.90m to win the women's long jump. Veronica Vancardo took a nasty spill in the women's 800m semi-final that was won by Briton Keely Hodgkinson. "I was talking with Veronica, who fell unfortunately. She still has her teeth and she will be ok. Actually, this is one of my worst nightmares but this is sport and it happens sometimes."
The three-day Ultimate Championship continues on Saturday 12th.
