Holland's Nadine Broersen won the first medal of the World Indoor Championships on Friday, claiming victory in the pentathlon in Sopot.
The 23-year-old took a lead of 101 points into the final event, the 800 metres, and sixth place was enough to secure the gold medal by 62 points from Canada's Brianne Theisen-Eaton.
Theisen-Eaton finished second in the 800m to move up from third and claim silver ahead of Ukraine's Alina Fyodorova, who could only finish seventh.
Fyodorova claimed the bronze by just six points from American Sharon Day-Monroe, who won the 800m in a personal best of two minutes 9.80 seconds.
The only other event decided on the opening day was the men's shot put, with American Ryan Whiting successfully defending his title with a best of 22.05 metres in the fourth round.
Germany's David Storl took silver with 21.79m and New Zealand's Tomas Walsh the bronze with 21.26m, relegating home favourite Tomasz Majewski to fourth.