If Adam Schenk is going to win his first PGA Tour title, he's going to have to hold off a pair of heavyweights to do it.

Schenk carded a 70 on Saturday to sit at 8-under par at the Valspar Championship at Palm Bay Harbor, Fla., leading Jordan Spieth (third round 69) and England's Tommy Fleetwood (69) by one stroke.

Taylor Moore (69), Cody Gribble (70) and Webb Simpson (68) are tied for fourth, two shots off the lead. England's Matt Wallace (70), Patton Kizzire (67) and Wyndham Clark (70) head into Sunday's final round at 5 under, clustered together at T7.

Schenk has held the lead or co-lead after each round at Innisbrook Resort. He posted three birdies against two bogeys in the third round, but it was enough to remain atop the leaderboard on moving day. He birdied two of his final three holes, including No. 18.

"Battle all day. Not a ton went our way early," Schenk said. "We really hung in there. (My caddy) did a great job of telling me that everybody's going to struggle today, it's windy, it's difficult. You're going to get some bad breaks, you're going to get some good breaks, just wait for 'em. We got ours on 16 and 18. The birdie on 18 was just an added bonus."

Spieth had a strong start to his round in pursuit of a repeat win at the event. He eagled No. 1 but carded four bogeys on the back nine for five total. Five birdies helped negate the bogeys.

"It was a really nice start," Spieth said. "I've kind of not really had my best stuff the last two days with my swing and today I managed it really well around here. ... I made a few too many mistakes but overall in these conditions I think I would have signed for 2-under."

Fleetwood, meanwhile, was one of three players with a bogey-free round on Saturday, recording two birdies.

"I think the first thing to look at is bogey-free," Fleetwood sad. "I made no dropped shots, I never went backwards once. I think that was just, they're always nice, no matter where you play nor when you're playing, but on a day like today when it's really tough, I felt like that was really important. Overall just happy with how patient I stayed."

Kizzire and Doc Redman (68) also turned in clean cards.