Dustin Johnson moved a step closer to the number one ranking by taking the lead as the second round of the Genesis Open was finally completed on Saturday.

After play was suspended for most of Friday, a further rain delay on the morning of day three pushed back the schedule at Riviera Country Club even further but once the action resumed Johnson took charge.

A second successive round of 66 leaves him one shot clear on 10 under par as he chases the victory he needs to end the tournament top of the rankings.

That can only happen if current number one Jason Day finishes worse than a three-way tie for third - and the Australian lies in a tie for 40th on two under.

Padraig Harrington followed up his opening 67 with a one over 72 but still comfortably made the cut on three under - the same score as Graeme McDowell, who finished his second round on Friday.

Shane Lowry withdrew as he would have had to eagle the final two holes of his delayed second round to make the cut.

Japan's Hideki Matsuyama also started the week with hopes of topping the rankings but endured a torrid second round, making nine bogeys and missing the cut.

Johnson's flawless second round leaves him a shot ahead of fellow Americans Pat Perez and Cameron Tringale, who each birdied the 18th.

England's Like Donald and world number six Jordan Spieth are well placed to make a charge in the final two rounds, sitting four and five shots back respectively.

Those who made the cut will return on Saturday evening to complete as much of the third round as possible.