spieth held his nerve in sunday 's final round to keep control of the season 's first major championship , matching tiger woods ' record of an 18-under 270 and finishing four shots clear of the field .
speaking in butler cabin as he looked to hold off the attentions of two major champions in the form of phil mickelson and justin rose .
jordan spieth has hailed the ` most incredible week ' of his life after winning the masters at augusta in 39 years .