Australia's Adam Scott has boosted his chances of qualifying for the lucrative season-ending PGA Tour play-offs finale by launching himself into contention at the BMW Championship.
Scott carded a one-under 69 on Friday to be one-over after two rounds and rocket himself up to a five-way share of fifth on the leaderboard.
The 2013 Masters champion - who started the week 38th on the FedExCup standings - needs at least a 17th placing this week to advance to the $45 million ($A62.5m) Tour Championship in Atlanta, Georgia, but can lock up a place with a seventh-place finish.
Scott is just two shots off the pace set by halfway co-leaders Rory McIlroy (69) and Patrick Cantlay (68), who are the only two players under par as the Olympia Fields Country Club continued to torment 69 of the world's best golfers.
While Scott has, so far, coped best of the Australians in the toughest test the PGA Tour has seen this year, three of his countrymen have struggled.
Jason Day's hopes of vaulting himself into the FedExCup top 30 to extend his play-offs campaign nosedived with a 74 leaving him at 10-over.
The former world No.1 is tied for 61st, needing at least a top-eight result to advance.
Cameron Smith - who started the week in 26th spot in the season's standings - is teetering on the brink with a 73 on Friday dropping him to eight-over and tied-55th.
He needs a finish of 33rd of better to advance and join Marc Leishman, who is fortunately already qualified for Tour Championship.
The Victorian added a 78 on Friday to his first-round 80 to round out the field at 18-over.
McIlroy - who admitted to going through the motions without spectators to provide the atmosphere - dropped shots coming home as conditions worsened at the course outside Chicago but was still please with his efforts.
"I think the test is what's helped me focus and concentrate because if you lose focus out there for one second ... just one lapse in concentration can really cost you around here," the world No.4 said.
Cantlay's eventful round included an eagle, four birdies, two bogeys and a double bogey as the American carded the equal-low round of the day.
FedExCup standings leader Dustin Johnson (69) is even-par and alongside first-round leader Hideki Matsuyama (73) tied for third going into the weekend.
For those playing well - anywhere within a few shots of par - Olympia Fields has been an enjoyable challenge.
For others it has been tough.
It's a massive change from last week, when Johnson won by 11 shots at 30-under 254.
"Last week was fun, too," Johnson said. "But this week is more of a grind, that's for sure."
Tiger Woods' poor putting led to a miserable round of 75 that included five bogeys, a double bogey and two birdies, with his PGA Tour seemingly two rounds from being over.