Complex sentence: Higgins had a poor 2011/2012 season, as he failed to reach the semi-finals of any of the ranking events, although he did lose at this stage in the Masters 4--6 to Shaun Murphy.
Split into simpler sentences: Higgins had a poor 2011/2012 season, as he failed to reach the semi-finals of any ranking event. He did reach the semi-finals of the Masters, but lost 4--6 to Shaun Murphy.