spieth became the first player ever to reach 19 under par at augusta and only a bogey on the 18th prevented him from adding the 72-hole scoring record to the 36 and 54-hole records he set on friday and saturday .
the 21-year-old also became the second youngest champion behind tiger woods - whose 18-under total he equalled - after a closing 70 left him four shots ahead of justin rose and phil mickelson .
jordan spieth admitted he would probably sleep in the green jacket after claiming his first major title .