Justin Thomas, Marc Leishman Share Lead at Dell Technologies Championship 2017

Through three rounds of the 2017 Dell Technologies Championship at TPC Boston in Norton, Massachusetts, PGA champion Justin Thomas and Marc Leishman sit atop the leaderboard.

The pair are tied for first place after going 12-under over the first three days. Thomas carded an eight-under 63 on Sunday, while Leishman finished the round at six under.

Consistency was the key to Thomas' success Sunday for the second day in a row. He put together another bogey-free round after doing just the same Saturday.

Golden State Warriors star Andre Iguodala commented on Thomas' performance:

Thomas still struggled somewhat off the tee, but his 10 fairways landed on 14 drives were his best of the tournament so far. His approach game more than made up for any issues with his driver. He reached 16 greens in regulation.

Thomas' putter was also in perfect working order, as evidenced by the 49-foot putt he sunk on No. 12 to earn a birdie, courtesy of the PGA Tour's official Twitter account:

Should Thomas outpace Leishman on Monday and claim the title, he'd join select company, according to ESPN.com's Jason Sobel:

One catastrophic mistake could tank Thomas' odds of coming out on top, though, given how tightly packed the leaderboard is.

Like Thomas, Leishman avoided making any critical errors. He reached all but one green in regulation and gained 1.857 strokes on his approach to the green, a vast improvement from the second round, when he lost 0.487 strokes during his approach, according to PGATour.com.

Leishman began his round with two birdies in the opening four holes but cooled off a bit over the next eight. Between Nos. 5 and 12, he carded one birdie before exploding with three straight birdies between the 13th and 15th holes.

The fact he parred the final three holes is somewhat of a missed opportunity since he was unable to get ahead of Thomas. Being in a tie for the lead is still a strong position to be in as a tournament enters its final day.

Not only will Thomas have to worry about Leishman, Jordan Spieth and Dustin Johnson are also lurking a little further down the leaderboard after each golfer carded a five-under 66.

Spieth closed Sunday with three birdies in his final five holes to move to within striking distance of Thomas. The PGA Tour shared a replay of his approach on No. 17 to set up an easy birdie putt:

Johnson will have a little more work to do than Spieth, since he's three shots back, whereas Spieth needs to close a two-shot gap on Thomas and Leishman. Like Spieth, Johnson used a hot streak near the end of the round to carry much of his overall performance. Four of his five birdies came over the last five holes before he headed for the clubhouse.

In order to move into first place, Johnson will likely need to get going a little earlier so as not to find himself needing to make up too much ground in too little time.