Australia's Marc Leishman has smashed Tiger Woods' tournament record in scoring a wire-to-wire victory at the US PGA Tour's rich BMW Championship in Chicago.

Starting the final round with a five-shot lead, 33-year-old Leishman carded a four-under-par 67 at Conway Farms to finish at 23 under par, five strokes clear of Rickie Fowler (67) and Justin Rose (65) who tied for second.

Fellow Australian Jason Day continued his late season resurgence with a 69 to be outright fourth at 16 under .

Leishman's total score of 261 was one shot better than the existing 72-hole tournament record of 262 Woods posted in 2007.

BMW Championship final standings -23 Marc Leishman (AUS)

-23 Marc Leishman (AUS) -18 Justin Rose (UK)

-18 Justin Rose (UK) -18 Rickie Fowler (USA)

-18 Rickie Fowler (USA) -16 Jason Day (AUS)

-16 Jason Day (AUS) -15 Matt Kuchar (USA)

-15 Matt Kuchar (USA) -15 Jon Rahm (SPA)

It is Leishman's second win of 2017, following his triumph at the Arnold Palmer Invitational in March, and his first wire-to-wire victory on the PGA Tour, having led after leading all four rounds in this penultimate FedEx Cup play-offs event.

The Warrnambool product's win also comes with the added bonus of climbing into the top five seeds for this week's Tour Championship.

The top five, led by Jordan Spieth, are guaranteed to win the $US10 million FedEx Cup bonus if they win the Tour Championship at East Lake Golf Club in Atlanta.

Leishman would become the first Australian to do so since the FedEx Cup play-offs were created in 2007.

Day, who also won the BMW wire-to-wire in 2015, climbed up the FedEx standings to 15th, meaning he is an outside chance of claiming the FedEx Cup.

Although Leishman held his five-shot cushion, it was not without drama and several challenges from the 70-man field.

Leishman will now climb into the top five seeds for this week's Tour Championship. ( AP: Charles Rex Arbogast )

Leishman endured a shaky start with several errant tee shots and a bogey at the fifth but bounced back with a birdie at the par-3 sixth to calm the nerves.

With world number 10 Fowler hot on his heels after two opening birdies and several clutch par saves, the turning point came at the par-5 eighth when Fowler failed to match Leishman's birdie.

A bogey at the par-4 13th saw Rose come within two shots of the Victorian, but three birdies in his last four holes — including a 20-foot birdie putt on the last — locked up Leishman's third career PGA Tour victory.

Rounding out the Australian contingent on the leaderboard was Brisbane's Cameron Smith, who suffered a crushing end to his season with a 70 dropping him to 12th at 11-under and he will miss out on advancing to the 30-man Tour Championship.

AAP