Complex sentence: Despite failing (by four winners) to pass Hanagan in the title race, 2011 was De Sousa's best-ever season; while Hanagan has suggested he may not try for a third successive title, De Sousa has no such qualms.
Split into simpler sentences: Despite failing (by four winners) to pass Hanagan in the title race, 2011 was De Sousa's best-ever season. While Hanagan suggested he may not try for a third successive title, de Sousa had no such qualms.