Rickie Fowler ended the day at five under, with Tony Finau at two under and Jordan Spieth struggling at even par alongside Johnson after a wildly inconsistent round.
In the second round of the 2018 Mayakoba Golf Classic, Matt Kuchar registered eight birdies on his way to his second-straight 7-under 64, good enough for 14-under for the tournament and a two-stroke lead over the field heading into the weekend.
Hickok also played college golf at Texas and lived with Spieth in Dallas until a few months ago, when all the roommates had to find other arrangements as Spieth prepares for his marriage to Annie Verret.
Sharma, who is playing his seventh week on the trot, opened with three bogeys in first holes and ended in a similar manner for 71 at the penultimate event of the European Tour.
She has taken on the role with the seven-time PGA Tour event victor previously. "I just had that one challenging hole".
A total of 15 players are sitting just a shot further back, with defending champion Patton Kizzire among those to hit an opening round of 65.More news: Houston Rockets in talks with Carmelo Anthony over his role on team
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Also at 65 were Bud Cauley as he returns from a vehicle accident at the Memorial in early June, defending champion Patton Kizzire, who made back-to-back eagles on the par-5 5th hole and by holing out on the par-4 6th, and Sydneysider Matt Jones.
He still keeps upbeat on and off the golf course and decided while in Las Vegas (a tie for 57th) to play Mayakoba.
Kuchar has slipped to No. 40 in the world, failed to reach the third round of the FedEx Cup playoffs for the first time in a decade and did not play in the Ryder Cup for the first time in 10 years.
Johnson's caddie Damon Green was taken ill with four holes remaining, suffering in the Mexican heat, and Kuchar came to the rescue by recommending the watching Sybi.
"It's kind of nice to look back and know that I've won on every stage", said Hickcok, who was also a two-time victor on the Mackenzie Tour a year ago. "I ended up making bogey there and par on the par-5 13th, so still felt like I was very much in control".
".it's got signs now of righting the ship and turning into a great start to. maybe it's a great finish to '18, great start to '18-19, however you want to classify the calendar", he said.