Portrush - Ireland's Shane Lowry is on the brink of a hugely popular first major win as he holds a four-shot lead over Englishman Tommy Fleetwood heading into the final round of the Open Championship on Sunday.

Lowry delighted the thousands of fans following him around the Portrush course in the first Open to be held in Northern Ireland since 1951, with an eight-under par round of 63 to seize the lead on Saturday.

His 16-under overall total of 197 is the lowest after 54 holes in British Open history.

However, Lowry's chances of beating the overall record to par of 19-under set by Tiger Woods at St. Andrews in 2000 could be undone by bad weather.

After glorious conditions that allowed Lowry to go low on Saturday, heavy rain and strong winds are expected to return on Sunday so his tee time has been moved forward to 14:47 SA time.

"I know tomorrow is going to be a difficult day. I know there's some bad weather coming in, but I'm in a good position," said Lowry.

"I just have to do what I've been doing all year and hit the reset button tonight and go out there and shoot as good a score as I can tomorrow."

Fleetwood is also looking for his first major after a starring role in Europe's Ryder Cup victory last year.

The world number 20 was in fine form on Saturday with a bogey-free round of five-under.

"I'm looking forward to it," said Fleetwood of his final round showdown with Lowry.

"It's going to be another chapter in my career, no matter what happens and it's going to be a very special day."

Fleetwood has a two-shot advantage over J.B. Holmes on 10-under, but a host of the world's best players are poised to make their move should the leaders falter.

World number one Brooks Koepka has not failed to finish in the top two in all three majors so far this season and will tee off in the penultimate group with Holmes after two birdies in his final two holes on Saturday took him to nine-under.

And Koepka is hoping Lowry and Fleetwood are blown off track.

"Thankfully it's going to blow tomorrow," said the four-time major champion.

"Here you need some wind, you need some rain. You need anything that can kind of go your way. And that's got to be an advantage."

World number three Justin Rose, who finished tied for second at last year's Open, is also on nine under.

Two of the most talented players on tour never to have won a major, Lee Westwood and Rickie Fowler, tee off at eight-under.

Jordan Spieth, Open champion two years ago, Jon Rahm, Danny Willett and Tony Finau also form a dangerous group at seven-under with the potential to shoot themselves into contention.

Scores from the third round of the Open Championship at Royal Portrush on Saturday (par 71):

197 - Shane Lowry (IRL) 67-67-63

201 - Tommy Fleetwood (ENG) 68-67-66

203 - J.B. Holmes (USA) 66-68-69

204 - Brooks Koepka (USA) 68-69-67, Justin Rose (ENG) 69-67-68

205 - Rickie Fowler (USA) 70-69-66, Lee Westwood (ENG) 68-67-70

206 - Jon Rahm (ESP) 68-70-68, Jordan Spieth (USA) 70-67-69, Tony Finau (USA) 68-70-68, Danny Willett (ENG) 74-67-65

207 - Cameron Smith (AUS) 70-66-71, Dylan Frittelli (RSA) 68-69-70, Alexander Noren (SWE) 68-71-68, Henrik Stenson (SWE) 70-69-68, Andrew Putnam (USA) 70-67-70, Matt Kuchar (USA) 70-68-69

208 - Xander Schauffele (USA) 74-65-69

209 - Park Sang-Hyun (KOR) 69-72-68, Justin Thomas (USA) 71-70-68, Patrick Reed (USA) 71-67-71, Russell Knox (SCO) 70-71-68

210 - An Byeong-Hun (KOR) 73-67-70, Erik van Rooyen (RSA) 70-68-72, Justin Harding (RSA) 71-65-74, Webb Simpson (USA) 68-71-71, Matthew Fitzpatrick (ENG) 71-69-70, Tyrrell Hatton (ENG) 68-71-71

211 - Romain Langasque (FRA) 69-72-70, Rory Sabbatini (SVK) 70-70-71, Kevin Kisner (USA) 70-71-70, Dustin Johnson (USA) 72-67-72, Tom Lewis (ENG) 75-68-68, Robert MacIntyre (SCO) 68-72-71, Graeme McDowell (NIR) 73-70-68

212 - Lucas Bjerregaard (DEN) 70-68-74, Sergio Garcia (ESP) 68-73-71, Mikko Korhonen (FIN) 72-69-71, Ernie Els (RSA) 71-69-72, Aaron Wise (USA) 72-69-71, Lucas Glover (USA) 72-69-71, Patrick Cantlay (USA) 70-71-71

213 - Yuki Inamori (JPN) 70-73-70, Hwang Inn-Choon (KOR) 72-71-70, Joost Luiten (NED) 73-69-71, Ryan Fox (NZL) 68-75-70, Charley Hoffman (USA) 70-73-70, Stewart Cink (USA) 74-68-71, Doc Redman (USA) 71-71-71

214 - Thomas Pieters (BEL) 72-68-74, Yosuke Asaji (JPN) 72-71-71, Louis Oosthuizen (RSA) 70-72-72, Andrew Wilson (ENG) 76-67-71

215 - Bernd Wiesberger (AUT) 70-71-74, Adam Hadwin (CAN) 74-69-72, Benjamin Hebert (FRA) 73-69-73, Francesco Molinari (ITA) 74-69-72, Kyle Stanley (USA) 75-67-73, Paul Casey (ENG) 72-70-73, Matt Wallace (ENG) 73-70-72

216 - Branden Grace (RSA) 70-71-75, Bubba Watson (USA) 72-71-73, Jim Furyk (USA) 73-68-75, Kevin Streelman (USA) 77-65-74, Callum Shinkwin (ENG) 70-71-75

217 - Thorbjorn Olesen (DEN) 72-68-77, Jason Kokrak (USA) 74-69-74

218 - Nino Bertasio (ITA) 72-71-75, Kiradech Aphibarnrat (THA) 68-73-77, Eddie Pepperell (ENG) 70-72-76, Paul Waring (ENG) 75-68-75

219 - Shubhankar Sharma (IND) 70-72-77

220 - Ashton Turner (ENG) 69-74-77