Augusta, Ga. ? The field chased furiously, but the fresh-faced 21-year-old slipped from its grasp.

Rory McIlroy’s bid to become the second-youngest champion in Masters history took a big leap forward Saturday with a third-round 70 that lifted him to 12 under for the tournament. The Northern Irishman is four strokes ahead of the field at Augusta National Golf Club and looking far more relaxed on the course than many of his more decorated competitors.

“I feel comfortable,” McIlroy said. “Comfortable with my game, comfortable with the way I’ve prepared, and all of the sudden I’m feeling comfortable on this golf course.”

McIlroy turned in a workmanlike first nine, overcame a bogey at No. 10, then found birdies on 13 and 15. But the exclamation point came at 17. From the back of the green, his 20-foot putt first broke right, then left, then dropped in. He lifted his putter and pumped his fist twice, allowing himself a rare burst of emotion.

“It was a bonus for that putt to go in,” McIlroy said. “Been waiting for one to go in all day.”

McIlroy, who has stressed patient play all week, said he knows he still has work to do today.

“I’m not getting ahead of myself,” he said. “I know how leads can dwindle away very quickly.

“Four shots on this golf course isn’t that much.”

Jason Day, who started the day two shots back and was paired with McIlroy, shot an even-par 72 and fell into a tie for second.

“Rory, the way he’s hitting the ball, he can go out there and shoot a couple under par and win,” Day said. “There’s a lot of pressure on us to go out there and score early to put a little pressure on him.”

Angel Cabrera, Charl Schwartzel and K.J. Choi are tied with Day at 8 under. Cabrera, the 2009 Masters champion, shot a 67 on Saturday. Schwartzel, quietly in contention all week, had a 68. K.J. Choi, paired with Tiger Woods in the third round, shot a 1-under 71.

The final three pairings today are decidedly international. Fellow Australians Day and Adam Scott tee off at 1:20 p.m., followed by Choi (South Korea) and Schwartzel (South Africa) at 1:30 p.m. and McIlroy and Cabrera (Argentina) at 1:40 p.m. The top American on the leaderboard is Bo Van Pelt in eighth. He will play with Englishman Luke Donald and tee off at 1:10 p.m.

Nineteen of the past 20 Masters champions have played in the final pairing of the final round.

The low scoring from the first two rounds continued Saturday. In all, 37 players are under par for the tournament. Through 54 holes, there have been 39 rounds in the 60s, including 11 in the third round.

Four-time Masters champion Tiger Woods, who vaulted into contention with a blistering stretch of birdies Friday, never quite found his game Saturday. He shot a 74 and is 5 under for the tournament, seven strokes behind McIlroy.

“(I’m) pleased with the way I played; I just made nothing,” Woods said. “I had so many putts early that looked like they were going to go in but just didn’t go in.”

Woods’ position is only slightly better than that of defending champion Phil Mickelson, who again was unable to make a run. He finished with a third-round 71 and is 3 under for the tournament. In order to win, he would have to surpass the record for largest final-round deficit — nine strokes — ever overcome by a Masters champion.

If McIlroy holds on to win today, he will be just seven months older than Woods was when he blitzed the field in 1997.

Asked if a pairing with two-time major winner Cabrera would be a positive or a negative, McIlroy once again reiterated he is focused only on himself.

“It doesn’t matter who’s beside me, to be honest,” he said. “As I’ve said before, all I can do is control myself and my golf game.

“I just have to go out and concentrate on myself.”