 Complete the following phrase:  Ferreira stepped down at the end of the 200910 season and was replaced by André Villas-Boas, a former assistant of Mourinho at Porto, Chelsea, and Internazionale. In a single season, Villas-Boas guided the team to a record-matching four titles, including victory in the 201011 UEFA Europa League. Their triumphant campaign started in the play-off round, where they overcame Belgian side Genk to reach the group stage. Porto topped their group undefeated, only dropping points against Beşiktaş. In the round of 32, despite a second-leg home loss, they eliminated the 200506 and 200607 UEFA Cup winners Sevilla, setting up a tie with CSKA Moscow. Porto defeated the Russians in both legs and advanced to the quarter-finals, where they were paired against another Muscovite club, this time Spartak Moscow. Two prolific displays, which included a hat-trick by Radamel Falcao, sealed a 103 aggregate win for Porto. In the semi-finals, Falcao went one better and scored four goals in a first-leg 51 win against Villarreal, which all but confirmed the clubs fourth major European final.ref name201011ref The 