sentences:  Sexton was part of Leinster's Celtic League winning side in 2007–08.On 2 May 2009 he established himself in the Leinster first team, replacing the injured Argentine fly-half Felipe Contepomi as an early substitute in the Heineken Cup semi-final to help Leinster beat rivals Munster a convincing 25–6.He then started in Leinster's home match against the Scarlets in the Celtic League, scoring 15 points (including a try) in a man of the match performance.