Blackburn will face Lithuanian side FK Vetra in the Intertoto Cup third round after UEFA expelled Legia Warsaw from the competition following crowd trouble at the weekend.
UEFA officials abandoned the second-round match in Vilnius after fans of the Polish club clashed with police and fired numerous missiles onto the pitch.
FK Vetra had been winning 2-0 when the hooliganism started.
As well as their expulsion from the Intertoto Cup this season, Legia will also be banned for one future campaign should they qualify within the next five years.
They have also been ordered to contact Vetra within 10 days to discuss compensation for the damage caused. The match has been awarded as a 3-0 win to Vetra by default.