(Reuters) - World number three Justin Thomas birdied two of his final three holes to grab a one-shot lead over Jon Rahm at the Zozo Championships on Saturday and set up a final round showdown with the Spanish world number two. Thomas started the day with a one-shot lead and ended it the same way, mixing six birdies with a single bogey at Sherwood Country Club for a scrappy five-under 67 to get to 19-under for the tournament. Rahm posted the round of the day: an error-free nine-under 63 highlighted by an eagle at the par five second. “It was a good fight, hung in there well,” summed up Thomas, who will be bidding for his 14th career PGA Tour win. “I felt like I definitely didn’t play as well as I did the first two days or didn’t have my best stuff by any means, but to shoot a round like that is huge on a course like this. “Usually I’m grinding to shoot a 1, 2, 3 under but here at Sherwood the scores are very low and you need to be able to, as crazy as it is, shoot five-under to keep pace.” While the world’s number two and three ranked players will have the spotlight, there will be plenty of challengers out ahead of them with 11 players within four of the lead on a the Thousand Oaks, California layout that is surrendering plenty of low scores. American Lanto Griffin briefly surged to the top of the leaderboard on the back of four straight birdies to open his round and held on for a four-under 68 to sit just two off the pace. Lurking three back are Colombian Sebastian Munoz (66) and Americans Ryan Palmer (66) and Patrick Cantlay (68), who has gone bogey-free through three rounds. Left near the bottom of the leaderboard after a horrific opening round, Tiger Woods had a bounce back 66 on Friday but the defending champion was unable to build on that effort returning a one-under 71. Woods arrived at one of his favorite venues chasing a recording-breaking 83rd PGA Tour win. But that mark will have to wait, with the 15-time major winner entering the final round 16 back of the leader.