Johnson takes Open lead

St Andrews - Zach Johnson was flying high at the top of a massively congested leaderboard early in the delayed final round of the 144th British Open on Monday but amateur Paul Dunne had a rocky start.

Louis Oosthuizen, who won the prized Claret Jug the last time golf's oldest major was held at St Andrews in 2010, rolled in a 20-foot birdie putt at the first as he moved to 13 under par through three holes.

But it is former US Masters champion Johnson who is the man to catch.

Johnson went out in 31 before making another birdie on 10 to hold first place on -15.

The chasing pack features Adam Scott, Jordan Spieth, Sergio Garcia, Jason Day and Oosthuizen. All are within two shots of the lead.