She took part in the under-23 race at the 2006 European Cross Country Championships and was 63rd overall, helping the Dutch women's team to fourth place.

At the 2009 European Athletics Indoor Championships she reached the semi-finals of the 800 m and then won at the 2009 European Team Championships First League meet (where she also helped the Dutch 4×400 metres relay team to the bronze medal.

[citation needed] Hak gained her first victory on the major circuit with a close win over Egle Balciunaite, running 2:00.53, at the Golden Spike Ostrava meeting.

At the major championships in Barcelona she ran a personal best of 1:58.85 in the 800 m to win the silver medal behind Mariya Savinova, making her the first Dutch athlete to medal in the event since Gerda Kraan in 1962 European Athletics Championships.

[2] Her new best also raised her to number three on the Dutch all-time lists behind Ellen van Langen and Stella Jongmans.