Spieth a bigger threat after frustrating miss

Jordan Spieth missed a chance at a historic Masters debut victory last year under the greatest pressure of his career but returns to Augusta National this week confident and comfortable.

The 21-year-old US star settled for becoming the youngest runner-up in Masters history on that occasion, closing the front nine on Sunday with back-to-back bogeys to surrender the lead to eventual winner Bubba Watson.

Spieth built on that experience and has added wins at last year's Australian Open and Hero World Challenge and last month's PGA Valspar Classic to reach fourth in the world rankings and move tantalyzingly close to his goal of overtaking Rory McIlroy to become the world No 1.