|The BMW Championship second-round leaderboard|
|-12 H Matsuyama (Jpn); -11 P Cantlay, T Finau (both US); -10 J Thomas (US); -9 A Hadwin, C Conners (both Can), L Glover, C Reavie, X Schauffele (all US), R Sabbatini (Svk)|
|Selected others: -8 T Fleetwood (Eng), R McIlroy (NI), -5 B Koepka (US); -4 P Casey, I Poulter (both Eng); -3 J Rose (Eng); G McDowell (NI); -2 T Woods (US)|
Hideki Matsuyama broke the Medinah course record by two shots with a stunning nine-under-par 63 to take the BMW Championship lead after round two.
The Japanese, 27, hit nine birdies and no bogeys to move to 12 under overall, one shot in front of Americans Patrick Cantlay and Tony Finau on Friday.
Justin Thomas and Jason Kokrak had both equalled the previous course record of 65 on Thursday.
“It seemed like every birdie chance I had I made the putt,” said Matsuyama.
Matsuyama was superb with the putter, sinking five birdie chances from beyond 15 feet, including a 30-foot effort at the 18th hole.
Having started the tournament 33rd in the FedEx Cup play-offs, Matsuyama is now projected second in the rankings. The top 30 players after this tournament will qualify for the Tour Championship on 22 August for the chance to become FedEx Cup champion.
Thomas shot a three-under 69 to move to 10 under overall, but fellow overnight leader Kokrak fell back to six under after a 73.
England's Tommy Fleetwood carded an impressive 66 to move up to eight under alongside Northern Ireland's Rory McIlroy, who shot 67. McIlroy is currently projected fourth, having come into the tournament in third place.
Tiger Woods hit five birdies but also four bogeys in a second consecutive round of 71.
The 15-time major champion said he would need to shoot “something in the mid-60s” in the two remaining rounds to move up into the top 30 and have the chance to defend his Tour Championship title.
World number one Brooks Koepka remains in projected first after a 71 moved him to five under overall, level with Patrick Reed, who won the first FedEx Cup play-off event, The Northern Trust, last week.
Defending FedEx Cup champion Justin Rose slipped back to three under after a 73, one shot behind fellow Englishmen Paul Casey and Ian Poulter.