Jason Day surges into the lead at BMW Championship

Rory Mc Ilroy struggled in the first round of the BMW Open

He goes into the weekend in the final group with fellow Australian Marc Leishman, who had a three-shot lead.

Day's 13-under total leaves him with a share of the clubhouse lead alongside world No.10 Rickie Fowler (64) and countryman Leishman, who has picked up four shots through 12 holes. "So the combination of those two things on a PGA Tour course is not a very good one", Leishman said.

"My last hole-in-one was at Turning Stone in 2008, so I've had a bit of a dry spell", Day said after his round.

Marc Leishman has a short memory when it comes to golf, which only helped him at the BMW Championship.

"Just like yesterday I gave myself heaps of opportunities and took advantage of them so happy to back up a 62 with a 64". He made a hole-in-one on the 17th hole with a 7-iron that turned into a payoff for multiple parties. "You go from scrambling for a par to making three [birdies] in a row", said the laid-back Leishman.

For Day - who won the event by six shots in 2015 - his hole-in-one came moments after he produced a chip-in eagle at the par-5 14th. BMW awarded $100,000 to the Evans Scholars Foundation, and then Day made a decision to give the vehicle he won to the Evans Scholars, which will yield another full, four-year scholarship for another student.

It hasn't been easy for everyone, particularly defending champion Dustin Johnson.

Rory McIlroy, requiring a top-five finish to have any chance of progressing to the season-ending Tour Championship, sits tied-50th following a two-under 69.

The world number 22 has won twice on the PGA Tour, including the Arnold Palmer Invitational in Florida in March.

The 28-year-old Northern Irishman captured the FedEx Cup title last year - and its $10 million bonus jackpot - but is now projected to finish 60th unless he makes a big move over the final two round, estimating he needed "a couple of 65s" to make any impact.

Leishman is now a projected 4th in the Fedex Cup points table and if he can remain inside the top four heading into next week's Tour Championship then he controls his own destiny in search of the US$10 million FedEx Cup bonus as any player inside the top five would win the top prize with victory in Atlanta.