All the pre-tournament talk may have surrounded Rory McIlroy, Jordan Spieth and Tiger Woods, but the trio could not make any real impact on the leaderboard early on, with Spieth and Woods enduring rounds to forget.
Matsuyama was one of the first on the TPC Shawgrass course and made the most of good conditions. Starting on the back nine, the Japanese star registered three birdies to take the turn in 33. A bogey at the 1st would prove his lone blemish, with two further birdies rounding off his 67.
Hearn too was atop the leaderboard early, with an eagle on the 11th, his second hole, setting the tone for a strong 33 on the back nine. The Canadian notched up birdies at the 7th and 9th to join Matsuyama at the top of the standings.
Hoffman recovered from a mid-round wobble to post his 67. Starting at the 10th the American was out of the blocks early, registering five birdies on the back nine. A triple bogey on the 1st – which began with a drive far too the right and never recovered – threatened to derail his round, but birdies at the 2nd, 4th and 9th steered Hoffman back on course.
Playing in the day's last group, Na started strongly with opening birdies at the 10th and 11th. After a bogey at the 15th, Na posted a birdie at 17 and picked up three further shots on the front nine for a strong start to the week.
Sitting one stroke back are Troy Merritt, Ben Martin, Billy Horschel, Brendon Todd, Charles Howell III and Derek Fathauer who all hit opening rounds of 68.
Fresh off his victory at the WGC-Cadillac Match Play Championship, world number one Rory McIlroy carded a respectable round of three-under 69.
Starting on the back nine, McIlroy began with five pars before getting his round up and running with a birdie at the 15th. At the 16th the Ulsterman showed his skill with a superb second shot from 205 yards that landed just six feet short of the hole and was converted for an eagle.
McIlroy responded to a bogey at the 1st with a birdie at the eighth to sit on three-under, where he is joined by a large group of players that includes Rickie Fowler, Jason Day, Sergio Garcia and Martin Kaymer.
Partnered with McIlroy, Spieth struggled on Thursday as he registered an opening 75. The world number two started poorly with bogeys on the opening two holes setting an unwanted tone.
While the 21-year-old managed birdies at the 13th and 2nd, bogeys on the 16th, 4th and 5th prevented any recovery. In truth Spieth will consider himself lucky to still be in with a chance of making the cut, with some good putting on the closing nine saving him from a worse fate.
Not for the first time this year Woods struggled with his swing, with a tee shot into the water at the 8th leading to a double bogey and an outward 37.
The former world number one recovered somewhat with birdies at the 14th, 15th and 17th, but a double bogey at the last after a pulled tee shot into the water resulted in a disappointing 73.