The 2002–03 season was the club's 44th season in the Turkish Super League and the club's 100th year in existence. After signing Romanian manager Mircea Lucescu, Beşiktaş won the league for the 12th time in club' history. Beşiktaş also had their most successful UEFA Cup run, by becoming a quarter finalist, however the club lost to S.S. Lazio 1–3 on aggregate, therefore eliminating them. Beşiktaş lost to Gençlerbirliği 3–4 in the quarterfinals of the Turkish Cup.
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Beşiktaş had their most successful run, by becoming a quarter finalist. In doing so, they became the second Turkish team to achieve the feat (Galatasaray achieved it in 2000).
^"2002-2003 Sezonu Şampiyonluğumuz" [Our Championship Title at 2002-2003 Season] (in Turkish). Beşiktaş J.K. 11 May 2016. Archived from the original on 30 August 2021. Retrieved 30 August 2021. En yakın rakibine sekiz puan fark atan takımımız, ligin bitimine bir hafta kala ezeli rakibimiz Galatasaray ile oynadığı maçta şampiyonluğunu ilan etti. Sergen Yalçın'ın 90. dakikada attığı muhteşem golle 100. yılında şampiyonluğunu ilan eden Beşiktaş'ın kadrosunda şu isimler bulunuyordu: "Oscar Cordoba, Göksel Gencer, N. Yasin Yıldız, Ronaldo Guiaro, Antonio Carlos Zago, Tolga Doğantez, A. Da Silva Mariano (Amaral), Enver Gayır, Zafer Demiray, Tümer Metin, Tayfur Havutçu, Bayram Bektaş, Yasin Sülün, Serdar Topraktepe, Daniel Gabriel Pancu, Eser Yağmur, Kaan Dobra, Ahmet Yıldırım, Sergen Yalçın, Tamer Tuna, Niyazi Güney, Engin Özçelik, İbrahim Üzülmez, Pascal Oliver Nouma, İlhan Mansız, Ali C. Begeçarslan, Ali Eren Beşerler, Ahmet Dursun, Federico Giunti, Constantin Marius Maldarasanu."