By Mark Lamport-Stokes AUGUSTA, Georgia, April 6 (Reuters) - The 80th Masters, which starts on Thursday, shapes up as one of the best in recent memory with world number one Jason Day heading a list of high-profile players in superb form over the past three months. Day is widely regarded as the pre-tournament favourite, having won six times in his last 13 starts, and the long-hitting Australian will be difficult to beat at Augusta National where he tied for second in 2011 and placed third in 2013. Jordan (Spieth) and Rory (McIlroy) and Henrik (Stenson) ... even Phil (Mickelson) is a favourite here. More...