|WGC Bridgestone Invitational second round|
|-4 J Day (Aus); -3 D Lingmerth (Swe); -2 W McGirt (US), E Grillo (Arg), S Piercy (US)|
|Selected others: -1 J Spieth (US); +2 P Casey (Eng); +3 P Mickelson (US); +5 J Rose (Eng)|
World number one Jason Day posted a one-under-par 69 to take a one-shot lead into round three of the WGC Bridgestone Invitational in Ohio.
Australian Day birdied the 16th and 17th holes but bogeyed the 18th to reach halfway on four under par.
Sweden's David Lingmerth also dropped a shot at the last but his three-under 67 lifted him up to second.
World number two Jordan Spieth is one under after a one-over 71 while England's Paul Casey (72) is two over.
"It was one of those days where you had to stay patient," said Day, who is bidding for a fourth PGA Tour win this season. "I'm just very pleased to shoot under par."