Miami - Australia's Aaron Baddeley fired a bogey-free six-under par 66 to seize a one-stroke lead after Saturday's third round of the PGA Tour's Puerto Rico Open.

The 37-year-old Aussie, seeking his fifth tour triumph and first since the 2016 Barbasol Championship, stood on 12-under 204 after 54 holes at Rio Grande.

"My game has been in a good spot for a while," he said. "It's a good start to the year. I hope to keep building on it tomorrow and see what happens."

American Nate Lashley birdied the 18th hole to grab second alone on 205, one stroke ahead of countryman Martin Trainer at the event, played while most of the world's top talent competes this week at the WGC-Mexico Championship.

Baddeley, whose best finish this season was a share of fourth at the campaign-launching Safeway Open last October in California, is excited about his chances.

Baddeley opened with back-to-back birdies, a wedge on his approach at the par-5 second the key shot there.

"It's always windy here so to get a couple birdies early was good," said Baddeley.

He followed with birdies at the par-5 fifth, par-4 ninth, par-3 11th and par-5 15th.

Lashley and Trainer hope to capture their first PGA titles.

Lashley sandwiched an eagle between bogeys at the first and third holes, then birdied the ninth and answered a bogey at 11 with birdies at 12 and 13 ahead of his closing birdie.

"Hopefully tomorrow I can control my nerves and win the golf tournament," Lashley said.

"I'm making good putts, driving it real well. I just have to do everything solid."

Trainer is trying to battle through in his debut season as well.

"There's a lot of pressure," he said.

"This is my first time I've truly been in contention at a PGA Tour event. I'm going to try and stay calm out there but I know I'll be really nervous and just do the best I can."

Leading scores after Saturday's third round of the PGA Tour's Puerto Rico Open at Rio Grande (USA unless noted, par-72):

204 - Aaron Baddeley (AUS) 70-68-66

205 - Nate Lashley 68-68-69

206 - Martin Trainer 70-67-69

207 - Joey Garber 68-74-65, Martin Piller 68-73-66, Wyndham Clark 70-68-69, Johnson Wagner 69-69-69, D.J. Trahan 69-67-71

208 - Roberto Castro 68-72-68, Andres Romero (ARG) 66-73-69, Jonathan Byrd 71-67-70, Ben Crane 68-69-71, Roberto Diaz (MEX) 68-68-72

209 - Roger Sloan (CAN) 70-67-72