Thiam, who turns 19 in August, rose to the occasion with no less than five new personal best scores in the two-day competition to take the European junior crown with a total score of 6298 points.
The Belgian youngster not only scored a world leading junior performance but also smashed the Belgian national senior record set by Olympic high jump champion Tia Hellebaut.
In the Italian town of Rieti, Thiam showed her huge potential by holding off talented Swede Sofia Linde (6081 points) and fellow Belgian Marjolein Lindemans (5831 points).
On top of scoring a Belgian national junior and senior record, as well as placing sixth on the all time junior rankings, Thiam also rewarded herself with a selection for the IAAF World championships in Moscow next month.