BMW Championship 2015: Leaderboard Scores and Highlights from Saturday

Jason Day maintained his stranglehold on the lead Saturday at the BMW Championship by virtue of a two-under 69, which puts him at 20 under par for the tournament.

The awe-inspiring Aussie looked somewhat ordinary during the third round at Conway Farms Golf Club in Lake Forest, Illinois, when compared to his opening two rounds, but he still boasts a comfortable six-shot lead over Scott Piercy and Daniel Berger:

Day enjoyed the best start of his career in a professional tournament Thursday and Friday by registering rounds of 61 and 63, respectively. Expectations were high entering the weekend, and even though his third round paled in comparison, it didn't need to be out of this world since he had already built a nice advantage.

As pointed out by the PGA Tour's official Twitter account, the reigning PGA Championship winner is dominating the tournament in essentially all areas:

He is on such a spectacular run that legendary golfer and broadcaster Johnny Miller doesn't believe anyone can touch him right now, according to Mike McAllister of PGATour.com:

After parring the first two holes of the round, Day increased his lead on the par-four third by knocking down this fairly lengthy birdie putt:

The rest of his front nine was pretty erratic as bogeys on the sixth and ninth canceled out birdies on the seventh and eighth.

The 27-year-old star began to round back into form on the back nine, though, as he birdied the 12th on the heels of this nearly perfect approach shot:

That marked the start of an up-and-down stretch as he traded birdies and bogeys from the 12th through the 15th holes.

Things settled down after that with pars on the 16th and 17th before Day birdied the par-five 18th to increase his lead to six strokes entering the final round of the tournament.

Saturday wasn't all about Day, however, as a number of talented golfers made some gains and moved up the leaderboard.

Chief among them was Rickie Fowler, who shot a five-under 66 for the second consecutive day and ended the round in a tie for fifth place.

The American birdied three of his final five holes, including this laser-guided putt on the par-three 17th after a great tee shot:

Unfortunately for Fowler, he seemingly feels as though he is in quicksand because of Day's excellent overall score:

The American will have an uphill climb Sunday in terms of challenging Day, but ESPN's Mark Schlereth was thoroughly entertained watching him regardless:

Rory McIlroy is in a similar position to Fowler, as his solid four-under 67 moved him into fourth place. The Northern Irishman and current world No. 1 has enjoyed a strong tournament and played well enough to win in most cases, but he'll need to play his best round of the tournament Sunday.

Dustin Johnson also played well Saturday to the tune of a three-under 68. He fired a 62 Friday after an even-par 71 in the first round. His strong play carried over to the first hole of the third round as he buried this long birdie putt from off the green:

"

Dustin Johnson's first 7 holes at BMW: +3 Dustin Johnson's last 30 holes at BMW: -13 He's T6 after this birdie. http://t.co/7zlXqczqWg

— PGA TOUR (@PGATOUR) September 19, 2015"

Johnson had his usual ups and downs on the front nine with three birdies, two bogeys and a double bogey, but he followed that up with four birdies on the back nine and is now in a tie for fifth place at 12 under overall.

Reigning Masters and U.S. Open champion Jordan Spieth's day was far more pedestrian as he settled for a one-over 72 and fell to a tie for 11th place.

Conversely, the unheralded Piercy's four-under 67 was one of the best rounds of the day, and it made him Day's closest competitor along with Berger entering the final round.

While there were certainly some strong rounds Saturday, no golfer did enough to strike fear into Day entering the fourth and final round of the BMW Championship.

According to McAllister, Day's six-shot lead is the biggest differential between first and second place after 54 holes this season:

Day flirted with a 10-shot lead for a period of time, and if he had been able to accomplish that feat, it would have been the first time it occurred through three rounds in 15 years, per GolfChannel.com's Justin Ray:

Although Day's lead may not be historic, it is sizable and perhaps insurmountable should he play even average golf Sunday.

If he does that and hoists the trophy, he will join elite company as a five-tournament winner in one season, which is something that has been only two other times over the past two decades, according to Ray:

Day has been a runaway train since winning the PGA Championship, and despite his showing moments of vulnerability Saturday, other contenders will need incredible rounds coupled with struggles from Day to have a chance.

Unless all those things happen, Day is poised to take the world No. 1 ranking and come close to clinching the FedExCup championship as well.

Follow @MikeChiari on Twitter.