Dustin Johnson heads leaderboard at Northern Trust Open

Dustin Johnson has recorded a five-under-par round of 66 to lead after the first round of the Northern Trust Open.

The world number 11 dropped just one shot to open up a slender advantage over a group of 11 players who ended the day on four-under.

Italy's Francesco Molinari and the in-form Jimmy Walker featured in that group, while Keegan Bradley and Rickie Fowler ended the day a shot further adrift.

Lee Westwood headed the English challenge on two-under-par, and he was followed by Justin Rose, who recorded a solid round of 70.