Adam Scott and Marc Leishman have surged into a tie for the lead at the British Open, while Jason Day is just a shot behind as they charge towards the Claret Jug midway through the final round at St Andrews.

Scott has taken down the opening nine at the Old Course in five-under 31 and then birdied the 10th to jump to 15 under for the tournament through 13 holes and take a share of the lead with former Masters champion Zach Johnson and Leishman.

Trying to bury the demons of 2012 when he bogeyed the final four holes to cough up a four-shot lead Scott is making a bold charge.

He earned some early luck when his approach to the first jumped the Swilcan burn and he buried a birdie putt.

He stalled for a few holes before knocking in four birdies in the last five on the front nine and added another on the 10th.

Leishman, a day removed from his tournament-best 64, birdied the first, third, fourth, fifth, ninth and 10th holes to have now played his last 28 holes in 14 under to join his countryman at the top.

Day, the overnight co-leader at 12 under, has birdied the fifth and sixth holes to get to 14 under just one back through nine.

Grand slam hopeful Jordan Spieth wasted no time in making his presence felt, hitting it in tight on the first and ramming home a birdie to get to 12 under.

Further birdies on the fifth and sixth had him primed before a four-putt double bogey on the eighth stalled his hopes.

A birdie on nine has him two back at 13 under.

Sergio Garcia is also 14 under through 11 holes while Johnson leads after 14 holes.

The last Australian to win the British Open was Greg Norman at Sandwich in 1993, but the last Australian to win at St Andrews was the late Kel Nagle in 1960.

Steven Bowditch sits at seven under through 15 holes.

Marcus Fraser (-7), Matt Jones (-6), Geoff Ogilvy (-5), John Senden (-5), Scott Arnold (-5), Greg Chalmers (-3), Brett Rumford (E) round out the Australian tilt.