Day of dominance in Chicago

Red-hot Aussie blazes to four-stroke lead at BMW Championship

It took a weather delay to slow surging Jason Day at the BMW Championship on Thursday, where the Australian's fireworks even overshadowed Jordan Spieth's hole-in-one.

Day launched his bid for a victory that could lift him to No 1 in the world in scintillating fashion, firing an eagle and nine birdies that put him 10-under when the horn sounded to end play shortly after he teed off on his final hole.