Katarina Johnson-Thompson won the women's heptathlon for the fourth British victory in five years at the Hypo Meet on Sunday after Jessica Ennis-Hill dominated the event from 2010-12.
Ranked third before the final discipline, Johnson-Thompson came second in the 800 metres to overtake leader Nafissatou Thiam of Belgium and Theisen-Eaton, last year's winner.
Johnson-Thompson won the long jump with a 6.70-metre effort and finished the competition with a personal best of 6,682 points to beat runner-up Theisen-Eaton, who set a Canadian record with 6,641.
"I am disappointed," Theisen-Eaton said. "I am not satisfied with my personal best because I still have something left in me. I just wanted it so badly."
Theisen-Eaton surpassed the record of 6,599 points set in 2012 by Jessica Zelinka of London, Ont.
Dafne Schippers was third with a new Dutch best mark of 6,545 points, edging fellow Dutchwoman Nadine Broersen by 9 points. Thiam dropped to fifth with 6,508.
"The current level in heptathlon is so high I didn't think I could win in this field," Johnson-Thompson said. "The javelin was a big surprise for me, and the 200 metres went very well."
Later, Olympic silver medallist Trey Hardee won the men's decathlon in the American's first completed event since finishing runner-up at the 2012 London Games.
Hardee, who won the 100 metres and the 110 hurdles, set a year's best mark of 8,518 points to beat European under-23 champion Kai Kazmirek of Germany by 47 points. Another German, Rico Freimuth, took third with 8,317.
"This victory is very sweet," said Hardee, who didn't finish his two decathlons last year at the U.S. and the world championships due to injuries. "It was a tough struggle with a young German having the event of his life."
Hardee led the competition comfortably after the pole vault but saw Kazmirek closing in after the American only finished the javelin throw in 10th and the concluding 1,500 metres in 12th.
"I've never been happier a decathlon is over," said Hardee, who also won the event in 2011 and was runner-up two years earlier. "It was tough because it wasn't going well."