Jason Day catches leaders at Pebble Beach with 8-under 64

Jason Day, of Australia, hits from the 17th tee of the Monterey Peninsula Country Club Shore Course during the first round of the AT&T Pebble Beach National Pro-Am golf tournament Thursday, Feb. 9, 2017, in Pebble Beach, Calif. (AP Photo/Eric Risberg) (The Associated Press)

Jordan Spieth looks over the fifth green of the Pebble Beach Golf Links during the third round of the AT&T Pebble Beach National Pro-Am golf tournament Saturday, Feb. 11, 2017, in Pebble Beach, Calif. (AP Photo/Eric Risberg) (The Associated Press)

From left to right, Jake Owen, Jordan Spieth and Dustin Johnson walk up the eighth fairway of the Pebble Beach Golf Links during the third round of the AT&T Pebble Beach National Pro-Am golf tournament Saturday, Feb. 11, 2017, in Pebble Beach, Calif. (AP Photo/Eric Risberg) (The Associated Press)

Jason Day took one step back and two birdies forward to complete an 8-under 64 and join Jordan Spieth and Derek Fathauer as the 36-hole leaders in the AT&T Pebble Beach Pro-Am.

The second round was not completed until Saturday morning because of a rain and fog delays.

Day was coming off four straight birdies at Spyglass Hill when play was stopped by dense fog. He resumed by missing the 13th green to the right, chipping to 4 feet and missing the par putt. But the world's No. 1 player bounced back with two straight birdies, including a 30-foot putt on the par-3 15th hole.

They were at 10 under and had a four-shot cushion over Patrick Reed, Pat Perez, Brandt Snedeker and Rick Lamb.