OLYMPIA FIELDS, Ill. — Rory McIlroy doesn’t need fans to keep his head in the game at the BMW Championship. Olympia Fields is so tough it won’t allow anything but his full attention on every shot.

McIlroy and Patrick Cantlay made their share of mistakes Friday and shrugged them off because that’s bound to happen on the toughest test the PGA Tour has seen this year.

By the end of another steamy afternoon south of Chicago, they were the sole survivors to par.

One week after McIlroy admitted to going through the motions without spectators around to provide the cheers, he had a 1-under 69 to share the 36-hole lead with Cantlay.

It was plenty tough for Tiger Woods, whose PGA Tour season appears to be two rounds from being over.

He didn’t have enough good shots to atone for his bad ones, and he had to make a 35-foot par putt on his final hole to shoot 75, leaving him nine shots behind. Woods was toward the bottom of the pack at a tournament where he needs to finish around fourth to be among the top 30 who advance to the Tour Championship.

Cantlay holed a 50-foot chip for birdie, and holed out a 50-yard wedge for eagle. He also missed the green on three of the par 3s, the last one leading to a double bogey. He finished with a 6-iron out of the thick rough and made a 40-foot birdie putt on the 18th hole. It added to a 68, matching the best score of the round.

They were at 1-under 139, one shot ahead of Hideki Matsuyama and Dustin Johnson, who were going in opposite directions when it was time to sign their scorecards. Matsuyama, the only player to reach 4 under at any point this week, dropped four shots over his last 10 holes for a 73. Johnson finished birdie-birdie for 69.

The phrase “U.S. Open” is being heard a lot more than “FedEx Cup” this week.

“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,” McIlroy said. “I think one of the big keys this week is just not making big numbers. If you hit it out of position, get it back in position, make sure that your worse score is bogey and move on. Honestly, bogeys aren’t that bad out here.”

For those playing well — anywhere within a few shots of par in this case — it was an enjoyable challenge. For everyone, regardless of the score, it was a grind.