He gained notable wins over Joey ten Berge and local player Marek Polak, eventually losing to Patrick Loos who won the tournament.

He then went on to win the 2008 Denmark Open, defeating Hungary's Nándor Bezzeg, Finland's Marko Kantele and Belgian Geert De Vos en route to the final where he beat Fabian Roosenbrand.

At the 2017 World Cup, Ratajski and Tytus Kanik lost 5–3 in the first round to the Irish team of Mick McGowan and William O'Connor.

He defeated two-time reigning champion Glen Durrant in the quarter-finals, Scotland's Cameron Menzies in the semi-final, and world number one Mark McGeeney 6–1 in the final for his first televised major title.

In February Ratajski became the first Polish player to win a PDC event, defeating Daryl Gurney 6–4 in the final of the sixth UK Open qualifier.

[16] His weekend “double header” win secured him a place at the 2019 PDC World Darts Championship, where he lost to Seigo Asada.

Ratajski also made the 2018 Players Championship Finals, where he beat Gerwyn Price and Adrian Lewis before losing to Danny Noppert, and the 2018 Grand Slam of Darts, where he was drawn in Group B.

He defeated Raymond van Barneveld and Adam Smith-Neale and losing to Michael Smith, which meant that he went through to the last 16 stage where he lost to Jonny Clayton.

On the first day of the tournament, the Poles defeated the Portuguese team (Jose de Sousa and Luis Ameixa) with some difficulty by 4–3 in legs.