AUGUSTA, Georgia, Apr. 12 (Xinhua) -- Jordan Spieth shot an 18-under 270 at the Masters on Sunday to clinch his first major title with a record-tying performance.

It was a start-to-end dominating performance of Spieth, who shot an 8-under 64, the best opening round at the Masters in 19 years, to seize control. And the second youngest champion, behind only Woods' 1997 effort in Masters history set tournament scoring records for both 36 holes (14-under 130) and 54 holes (16-under 210).

Spieth, 21, also set a Masters record with 27 birdies, two more than Phil Mickelson's mark of 25.

"It was very nerve-wracking today. I thought today might be a little easier than yesterday, having played around with the lead, but it wasn't,"Spieth said. "It's the most incredible week of my life. This is as great as it gets in our sport. This is a dream come true for me and to be able to -- I didn't break 70 last year, even having a chance to win, where I got edged out by Bubba here. But to shoot some low rounds and so see some putts go in out here and to hear the roars, it was remarkable."

Spieth build a two-shot lead in the final group last year in his Masters debut but faded to a runner-up finish behind Bubba Watson.

Mickelson and Justin Rose tied for the runner-up spot with 274, 14-under-par.