In the return leg at Anfield, Hartson fired the club's goal of the season with a strike past Jerzy Dudek into the top corner from over 25 yards out. Celtic won this match 2–0, progressing to the semi-final. After scoring the winning goal against Rangers at Ibrox in late April Hartson was plagued by a back injury which meant he missed the rest of the season, including the 2003 UEFA Cup Final. Nevertheless, he had played a major role in getting Celtic all the way through the tournament, with his goals in Liverpool and Vigo, as well as several assists. Celtic were defeated 3–2 in the final after extra time by José Mourinho's FC Porto.