Illinois, September 18

Jason Day missed a shot at carding the seventh 59 in PGA Tour history but still enjoyed a career-best round to grab a four-shot lead after the weather-delayed opening round of the BMW Championship on Friday.

Day, seeking a fourth win in six starts, returned to Conway Farms Golf Club after overnight thunderstorms with a 44-yard chip shot from deep rough standing between him and a magical 59. But his attempt was short by nine feet and he failed to make the birdie putt, leaving the 27-year-old Australian with an opening 61 in the third of the PGA Tour's four concluding playoff events in the season-long FedExCup race.

"Selfishly, a 59 would have been great and only a handful of guys have shot 59, and I understand what the history is, but right now winning the tournament is more important than shooting the 59," said Day, who could reach the top of the world rankings with victory this week. "Overall I hit a pretty good chip, but I thought it was just going to bounce a little bit more than what it did," he added.

Masters and US Open champion Jordan Spieth, playing with Day, was in a six-way share of second place at six under along with fellow Americans Bubba Watson, Justin Thomas, Daniel Berger, Kevin Na, and Harris English.

World No 1 Rory McIlroy (68) was seven shots back. Spieth also played the first two rounds of the last two FedExCup events with Day, the first of which the Australian won by six shots. And while Spieth played his final eight holes in six under this week, he was once again trailing Day who mixed nine birdies with an eagle and bogey.

"It is definitely challenging (to keep up with Day)," said world No 2 Spieth, who missed the cut in the first two FedExCup playoff events. "It's something that I struggled with."