Francesco Molinari had to wear a white boilersuit on his first visit to the Masters but he heads into the weekend at Augusta National in prime position to claim a coveted green jacket.

The Italian added a second round of 67 to his opening 70 to share the early clubhouse lead with Australia's Jason Day on seven under par, with former world number one Dustin Johnson a shot behind and England's Ian Poulter another stroke back following a 71.

Molinari's first experience of Augusta National was as a caddie for his brother in 2006 after Edoardo qualified by virtue of winning the US Amateur title the year before.

"I didn't learn much about the course because we were going sideways most of the time," Molinari joked in reference to Edoardo shooting rounds of 80 and 77 to comfortably miss the cut.

Molinari made his debut as a player in 2010 and recorded his best finish to date with a tie for 19th in 2012, but came into the event on the back of a stellar 12 months.

The 36-year-old has won four times since last year's Masters, including the Open Championship at Carnoustie, while he also became the first European player to earn a perfect 5-0 record in the Ryder Cup in Paris.

Beginning the day four shots off the lead, Molinari birdied the third, eighth and ninth to reach the turn in 33 and picked up further shots on the 12th and 15th before a superb two-putt from 75 feet for par on the last.

"It was good, pretty solid, not many mistakes and when I missed greens I missed them on the good side, leaving myself pretty easy up and downs so all in all a very good day," Molinari said.

"Now I'm just going to rest. The game is in good shape so I don't think I can gain much from hitting balls. Just get as much energy as possible for the weekend. There's going to be a lot of players in the mix and a very long way to go."

Day had needed on-course treatment for a back injury during the first round, but completed an opening 70 and matched Molinari's 67 on Friday thanks to six birdies and a solitary bogey.

Poulter enjoyed a massive slice of luck when his approach to the 13th stuck in the bank of Rae's Creek and allowed him to chip and putt for an unlikely birdie, but added: "I'm a little frustrated with a couple of missed opportunities towards the end there.

"But it's on the board and I am in position and it's going to be a good weekend. There's a long way to go and if you put yourself in position with nine to go the course opens up. As long as I am there or thereabouts and try to be super aggressive who knows what can happen."

Two birdies and one bogey in his first six holes took Tiger Woods to three under, but Rory McIlroy remained one over after covering the same stretch in level par.

McIlroy's opening 73 had left the Northern Irishman in a tie for 44th place overnight and needing to defy the odds to complete the career grand slam as the last 13 Masters winners all enjoyed a place in the top 10 after the first round.

Overnight joint-leader Brooks Koepka made it a three-way tie for the lead with a rollercoaster round of 71.

Koepka made a flying start with a birdie on the first, double-bogeyed the second after failing to escape from the trees at the first attempt and made just three pars in an erratic front nine of 37.

However, the 28-year-old kept himself in contention for a remarkable fourth major victory in his last seven starts with birdies on the 15th and 18th.