Australian rookie Jason Day has put himself in contention for a top-10 finish at the AT&T Pebble Beach National Pro-Am after a topsy-turvy third round of 68. The Queenslander mixed four bogeys with six birdies and an eagle on the 18th in an up-and-down round as he soared from a share of 43rd at the start of the day into a tie for 14th place at six-under-par. But he and the rest of the field are still chasing second-year player Dustin Johnson, who birdied all five of the par-five holes for a five-under 67 and a four-shot lead over former US Masters champion Mike Weir (69). Johnson, 24, is chasing his second PGA Tour title in just nine starts following his breakthrough win in the Turning Stone Resort Championship last year. Victory for Johnson, who is at 15-under for the tournament, would push him into the top 50 in the world and qualify him for the World Golf Championships-Accenture Match Play Championship and make him eligible for the first two majors. Not since Phil Mickelson&aposs seven-shot buffer in 2005 has a player held such a big margin heading into the final round at Pebble Beach. “It&aposs probably been in college since the last time I had a pretty big lead,” Johnson told the PGA Tour website. “You don&apost really go away from your game plan at all. I played well here the first day, and looking forward to tomorrow. Not going to change the game plan at all.” Overnight leader Retief Goosen dropped to outright third at 10-under after posting a 74 to fall five shots behind. Bob Estes and Mark Calcavecchia are a further shot back in a share of fourth place. Aussie Aron Price followed his opening two rounds of 68 and 69 with a disappointing three-over 75 to fall into a tie for 33rd. Compatriots Marc Leishman (69), Mathew Goggin (71) and Matt Jones (72) are on two-under. AT&T Pebble Beach National Pro-Am Round 3 -15: Dustin Johnson 65 69 67 -11: Mike Weir 67 69 69 -10: Retief Goosen 68 64 74 -9: Bob Estes 68 72 67, Mark Calcavecchia 67 69 71 -8: DJ Trahan 67 73 68, Kevin Chappell 68 72 68, Bill Lunde 67 70 71, Chris Stroud 69 69 70 -7: Sean O&aposHair 71 68 70, Shigeki Maruyama 69 73 67, Mark Brooks 68 69 72, Kenny Perry 71 70 68 -6: Vaughn Taylor 66 75 69, Charley Hoffman 66 70 74, Ted Purdy 68 72 70, Jason Day (Australia) 67 75 68, Spencer Levin 71 70 69, Kevin Stadler 71 71 68, Charlie Wi 68 69 73 Also: -4: Aron Price (Australia) 68 69 75 -2: Marc Leishman (Australia) 72 73 69, Matthew Goggin (Australia) 70 73 71, Matt Jones (Australia) 71 71 72 -1: Jarrod Lyle (Australia) 72 73 71