The American-based ace took a five-shot lead into the final round at the BMW Championship after carding a three-under par 68 in the third round.

It complemented his nine-under par 62 opening round effort and seven-under par 64 on day two of the Illinois competition.

American Rickie Fowler and fellow Australian Jason Day were tied for second entering the final day’s play.

Leishman fired eight birdies in round two to give himself a strong chance at taking out the title.

His third round included five birdies. His only blemishes were two bogeys.

Day praised his Australian compatriot’s efforts. 

Leishman has never led the first three rounds of a PGA Tour event and came from behind during his two PGA Tour wins – the 2012 Travelers Championship and the Arnold Palmer Invitational earlier this year.

“‘Leish’ is playing spectacular; he’s going to be very difficult to beat tomorrow,” Day said.

“I’ve got to come out and play really good golf because he’s not making any mistakes.

“He’s hitting it in the right spots on the greens and holing putts. That’s a good formula for success.” 

Leishman is currently ranked 22 in the world golf rankings – just one spot behind fellow Australian and former number one Adam Scott.

- With AAP