Entering the competition at 5.50m - a lower height than his usual starting point - made four successive clearances to start the competition well, also making light work of 5.80m, 5.90m and 6.00m.
Clearing 6.00m wasn't enough to hand "Mondo" the win, however, as Emmanouil Karalis of Greece was successful at the same height after two failed attempts.
The pair went head-to-head for the title at 6.10m, but both failed with their three attempts each. That meant that Duplantis was the winner, thanks to Karalis' failings at 6.00m. Sam Kendricks of the United States was third with a best vault of 5.80m.
It also means the American-born Swede won all eight pole vault competitions he entered in the 2025 Diamond League. The only one he missed, in Lausanne last week, was won by Karalis.
Having essentially been eliminated after his third failure at 6.10m, there was no chance for Mondo to have an attempt at breaking the world record yet again, which currently stands at 6.29m.
But with the 2025 World Athletics Championships less than a month away, the evening was not ideal for Duplantis as he continues his preparations for the biggest meeting of the year.
"I'm just happy that I could win and that was the most important thing ahead of the World Championship," said the Swede, speaking to Swedish television.
"It didn't feel that good, to be honest. I don't feel that good right now. The wind wasn't entirely perfect either," he added, concerningly.