If that improves, he'll put himself in better position to win his second career Colonial and 12th PGA Tour event.
"It just comes down to ball-striking," Spieth said. "I think I had one birdie look inside 50 feet today and I missed it. I'm going to need more than that, and so it was an off day ball-striking but it felt better than the other two days, even though it may not show it that way."
There are plenty of players in Spieth's path to his first victory since the 2017 British Open, starting with Na.
Na has shown an ability to post low scores at Colonial, including an 8-under 62 on Friday. But Na has struggled from this position before. He had a one shot lead going into the final round of the 2015 Colonial, but shot a 2-over 72 and tied for 10th.
For Na, he's approaching the final round like he would anything else.
"You see that white stone in the middle of the fairway? That's where I'm trying to be every hole," said Na, who predicted a 3-under 67 would seal the victory for him on Sunday.
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Finau is the highest-ranked player in contention at No. 16. He is looking for his second career PGA Tour win in the midst of a stellar season thus far.
"It would be huge for me," Finau said of winning. "I'm at a point in my career I don't feel like I need any kind of validation. I've played some good golf at some big events, but you know, I'm looking forward to tomorrow and the rest of the season to try and get another one under my belt."
Furyk is an intriguing contender, too, at 49-years-old and with 17 PGA Tour victories to his name. He, along with Hughes and Charley Hoffman (who is 3 shots off the lead at 6-under), posted the only bogey-free rounds Saturday.
Furyk hasn't won a PGA Tour event since 2015, but is showing his old form and has already topped the $2 million mark in earnings this season.