McIlroy full of confidence

All he has to do is play good golf.

"I'm sort of holding this ranking, I feel, based on how I played last year," admitted McIlroy, whose 2015 campaign was disrupted by a left ankle injury that forced him out of the British Open.

"But I've got a good run of events coming up to put another couple of wins on the board before the end of the year, and I feel I'm playing well enough to do that."

McIlroy regained the world number one ranking last week without lifting a club when Spieth missed the cut at the Barclays to bring his two-week reign at the top to an end.

Day, who reached a career-high third in the world with his PGA Championship triumph last month, won the Barclays to give himself a shot at the summit this week as well.

His 10.99 average world ranking points put him just 1.36 points behind the 12.35 of McIlroy, with Spieth in the middle on 12.22.

Before teeing off, at least, each man was willing to defer to another when asked who's the best right now.

"You'd have to say Jordan," said McIlroy, pointing to the 22-year-old Spieth's two major titles among four wins in 2015.

"I believe that Jason is number one right now," said Spieth, in deference to the red-hot Day's three wins since July.

Day, however, says the actual rankings don't lie.

"It's a two-year roll-over for a reason," the Aussie said. "I honestly believe that I'm playing some good golf right now (but) you can't look at the world rankings and say 'Yes I'm the best player in the world but I'm third in the world rankings."

The only thing for Day to do is play his way to the top. Like his rivals in the race, he said he won't be thinking about the ranking when he tees it up at TPC Boston in the second of four events in the US PGA Tour's FedEx Cup playoffs.

As McIlroy put it: "Winning tournaments and playing well takes care of all of that."

Spieth said the Big Three buzz isn't distracting.

"I'm not focused on what either one is doing on the leaderboard unless they're in the lead," he said of McIlroy and Day. "And then if they're in the lead, how do I get up there and surpass them?"

Spieth is aiming to bounce back after suffering just his third missed cut of the season in New Jersey last week. He's returned to an old set of irons after trying a new one at the Barclays, and said some work with coach Cameron McCormick had assured him there was no big problem with his game.

"There wasn't much to fix," he said. "It was more what I was making up in my head."

Day, in contrast, is coming in hot. After his record-setting 20-under par triumph in the PGA, he finished 19-under at Plainfield Country Club on Sunday to win the Barclays by six strokes.

"It's been quite a run," Day said, adding in an ominous note for his challengers: "I liked last week's venue, and I like this one even more."

The top 70 finishers in the 100-strong field for the $8.25 million event advance to the third playoff tournament, the BMW Championship in Chicago.

The Tour Championship in Atlanta caps the playoffs, with a $10 million bonus up for grabs to the final FedEx Cup series points leader.

AFP