Lukaku became the first player to ever score in nine Uefa Cup or Europa League matches in a row, as Inter Milan defeated 1 Bayer Leverkusen to reach Europa Cup Semis.
Lukaku controlled Ashley Young’s pass, turned a defender and slotted home for his 31st goal of the season.
Antonio Conte’s side will face the winner of Shakhtar Donetsk v Basel in the semi-final on 17 August, also in Dusseldorf.
The Italian side could have beaten Leverkusen by more goals with Lukaku forcing goalkeeper Lukas Hradecky into a good save and former Premier League players Christian Eriksen, Alexis Sanchez and Victor Moses going close after coming off the bench.
Inter are now only two games away from winning their first trophy since the Coppa Italia in 2011.
Also last evening Manchester United scored an extra-time penalty to see off FC Copenhagen and set up a potential Europa League semi-final against Fellow EPL contenders, Wolves.