O'Sullivan had another successful season in 2002/2003, reaching the last 16 in seven ranking tournaments. He began the season by winning the invitational Scottish Masters, defeating John Higgins 9–4 in the final. He reached the quarter-finals of the LG Cup, losing against eventual champion Chris Small; the last 16 of the British Open, losing against Paul Hunter, the quarter-finals of the UK Championship, losing against Drew Henry; and the quarter-finals of the Welsh Open, losing against Marco Fu. After this O'Sullivan won back-to-back ranking titles, defeating Hendry in the final of the European Open, and Higgins in the final of the Irish Masters. He reached the last 16 of the Scottish Open, before losing against Alan McManus. His only first-round ranking event defeat of the season came at the World Championship, when he lost 6–10 in the first round against the unseeded Marco Fu, despite making a maximum break in the match. This defeat saw him drop to number 3 in the rankings. He participated in the Premier League, but despite topping the table after the league stage, he lost 4–6 in the semi-final against Fu.