Jordan Spieth set out to defy the odds and move a step closer to a first Major Championship title as the 79th Masters Tournament resumed at Augusta National.
Spieth held a three-shot lead overnight lead after carding a superb opening 64 which was just one shot outside both the course record and the lowest score recorded in Major Championship history.
The last player to hold the outright lead after the first round and go on to win was Ben Crenshaw in 1984, although Trevor Immelman was joint leader on his way to the green jacket in 2008.
But Spieth showed no signs of faltering as he picked up birdies on the second and fifth to move to ten under par and four shots ahead of Australian Jason Day, with Ernie Els, Charley Hoffman, Justin Rose and Sergio Garcia another stroke behind.
Day had three-putted the opening hole but made amends with an eagle from ten feet on the par five second, while Els had reached six under with a birdie on the second but bogeyed the fifth and seventh before picking up a shot on the par-five eighth.
The best golf of the day so far was coming from 2012 runner-up Louis Oosthuizen, who was four under for his round and the tournament thanks to birdies on the first, second, fifth and eighth.
Tiger Woods had also made birdie on the first to get back to level par in just his third start of the year.
Conditions were again perfect for the early starters, but recent history suggested the odds were against those not already high on the leaderboard.
The last nine winners of the year's first Major Championship had been inside the top 10 after the first round, which was bad news for the likes of Rory McIlroy and defending champion Bubba Watson, who began the day joint 18th on one under.
And McIlroy had to wait until the penultimate starting time of 1:48pm to resume his bid to complete the career grand slam and win his third Major in succession.
The top 50 players and ties will make the halfway cut, along with any player within ten shots of the lead.
Spieth slapped his leg in frustration after missing from ten feet for birdie on the seventh but made amends in style on the next, hitting his third shot from 230 yards to three feet after pitching out of a fairway bunker.
The resulting birdie took the 21 year old to 11 under par - the lowest halfway total in Masters history is 13 under by Ray Floyd in 1976 - and five shots clear of Day and Hoffman
