|BMW Championship third-round leaderboard|
|-20 J Day (Aus);-14 S Piercy (US), D Berger (US); -13 R McIlroy (NI); -12 R Fowler (US), D Johnson (US), K Na (US); -11 J B Holmes (US), H English (US), J Thomas (US); Selected others: -9 J Rose (Eng); -6 P Casey (Eng); -3 R Knox (Sco)|
Jason Day will take a six-shot lead into the final round of the BMW Championship in Chicago after shooting a two-under-par 69 in round three.
The Australian, 27, is 20 under after mixing six birdies with four bogeys.
Americans Scott Piercy (67) and Daniel Berger (70) are tied for second on 14 under, one clear of Northern Ireland's world number one Rory McIlroy (67).
"I feel like I've left myself too much to do going into the last day," said McIlroy, who birded his last two holes.
Day, who will usurp McIlroy at the top of the rankings if he wins at Conway Farms Golf Club, said: "I just want to get some sleep. I'm not really thinking about the number one slot."
England's Justin Rose carded a one-under 70 to move to nine under, while compatriot Paul Casey (71) is on six under.