Merritt leads as Johnson fires opening-round 63
Dustin Johnson opened the Northern Trust with an impressive eight-under 63 as Troy Merritt took a one-stroke lead on Thursday.
Johnson, a two-time champion of the event, sits outright second after a bogey-free first round that included eight birdies.
The world number two made four birdies on his front nine before four straight beginning at the fifth hole at the first event of the FedEx Cup play-offs.
"It's a golf course I like. We played here in the Presidents Cup a couple of years ago and I've played a couple of other events here," Johnson said.
"I really like the golf course. I think it sets up well for me, and with the conditions, you've got to hit really good shots if you want to get it close to the hole, but with the soft conditions, you can be kind of aggressive."
Merritt carded a nine-under 62 to grab the lead as the American also fired a bogey-free opening round in New Jersey.
He tied a Liberty National Golf Club course record with his round, which featured nine birdies.
"We're in a good position now to contend for the championship," Merritt told reporters after his round.
"That's why we tee it up each week. Obviously this week, it's a little bit different with just trying to get into next week … and now we can shift our focus from winning the golf tournament."
Kevin Kisner and Jon Rahm are tied for third after shooting seven-under 64s in the opening round, sitting a shot ahead of Tony Finau, Webb Simpson, Rory McIlroy and Justin Rose.
Jordan Spieth made a solid start with a 67 and world number one Brooks Koepka opened with a 70 as Tiger Woods struggled.
Woods is back in a tie for 116th after battling to a four-over 75 that included a double bogey and five bogeys.
Defending champion Bryson DeChambeau is tied for 33rd after shooting a three-under 68.