Meanwhile, Olympic and world champion Duplantis suffered his first Diamond League defeat in three years.
In March, the 26-year-old broke the world record for the 15th time, with a jump of 6.31m slightly north of Stockholm, in Uppsala.
But the best he could achieve on Sunday was 5.80m, second behind Australian Kurtis Marschall (5.90m).
“I felt like I was pretty unfocused, that I wasn’t ready to compete at the highest level,” said Duplantis, who is getting married next week. “I feel bad for my fans and my family, but I’m not that angry.
“We have a saying in Sweden that says you’re either lucky in games or in love, and in some strange way I think there’s some message or something positive in this that says something about the commitment I’m about to make in my marriage.”
There was a home win in the men’s discus for Daniel Stahl, with the world champion’s throw of 69.60m edging Australia’s Matthew Denny (69.02) and Slovenia’s Kristjan Ceh (67.67).
Britain’s Lawrence Okoye was eighth with 64.02, slightly below his best mark of the season (71.88).
In the women’s 100 meters, Great Britain’s Amy Hunt ran a personal best of 10.97 seconds to finish second behind American Melissa Jefferson-Wooden. Dina Asher-Smith was sixth in 11.24.
British sprinter Jeremiah Azu was disqualified after a false start in the men’s 200 meters, which was won by American Kenneth Bednarek in 19.87 seconds, and South African Sinesipho Dambile was second in 20.10.
Great Britain’s Elise Thorner was second in the women’s 3,000m steeplechase, finishing almost 12 seconds behind Tunisia’s Marwa Bouzayani, who won in a record time of eight minutes 59.28 seconds.
Charlie Dobson was fifth in the men’s 400 meters, beating South Africa’s Zakithi Nene in 44.48 seconds.
The men’s 800 meters was won by American Cooper Lutkenhaus in a season’s best time of one minute 42.70 seconds, with GB’s Ben Pattison (1:43.70) and Jake Wightman (1:44.39) fourth and seventh respectively.
American middle-distance runner Yared Nuguse edged out 19-year-old Australian Cam Myers to claim victory in the men’s 1,500 meters.
There was another record in the women’s shot put: the Dutch Jessica Schilder recorded 20.89 m.