Adam Scott has retained the Australian Masters title despite a final day struggle in the face of a strong challenge from American world No.8 Matt Kuchar.

South Australia’s Nick Cullen finished fourth, five shots behind the winner.

US Masters champion Scott started the day five shots clear of Kuchar, but couldn’t maintain his fine form of the previous three days and fell two shots behind the American with four holes to play.

But on Royal Melbourne’s closing holes, it was world No.2 Scott who held firm, picking up a birdie on the par 5 15th, while Kuchar, two groups ahead, bogeyed the 16th then double-bogeyed the last.

That gave Scott a two-shot cushion entering his last two holes and he parred both to finish with an even par 71 to be 14-under 270 with second-placed Kuchar (68) two shots back and Fiji’s Vijay Singh (71) third at 10-under.

It keeps alive Scott’s hopes of claiming the Australian triple crown, having won last week’s Australian PGA on the Gold Coast and with the Australian Open to come in Sydney in two weeks.

Before that Scott will again take on Kuchar, Singh and others at Royal Melbourne this week when he partners Jason Day for Australia in the World Cup.

Scott started the day with a four-shot lead over Singh and three others and five clear of Kuchar.

But his day was hard work from the start.

He struck trouble on the par 3 fifth, when he went from one bunker to another and did well to ecape with bogey.

Scott birdied the sixth, but dropped another shot on the seventh.

By the time he completed the front nine in even par, Kuchar, two groups ahead, had reached five-under for the day and joined Scott on 14-under.

Kuchar, who bogeyed the second, had notched six birdies in nine holes from the third to 11th.

Scott edged back in front with a birdie on the 11th.

But he struck more trouble on the par 3 14th, when his tee shot found a horrible lie in a greenside bunker.

Scott’s second rolled into light rough on the opposite fringe and after chipping to less than three metres, he never looked like making the putt and took double-bogey.

That left Scott 13-under, one behind Kuchar, who soon doubled his lead with a birdie on the par 5 15th.

Scott birdied the same hole to cut the gap to one, before Kuchar bogeyed the 16th to rejoin Scott on 14-under.

But Kuchar was extremely unlucky on the 18th, finding the wall of a greenside bunker with his second shot and he could only jab his third onto the floor of the trap, on his way to double bogey.

That left Scott with a two-shot cushion with two to play and he parred both to complete victory.

Final scores

270: Adam Scott (AUS) 67 66 66 71

272: Matt Kuchar (USA) 71 66 67 68

274: Vijay Singh (FIJ) 72 68 63 71

275: Nick Cullen (AUS) 65 69 69 72

278: Matthew Griffin (AUS) 69 65 69 75, Ryan Fox (NZL) 68 71 66 73

279: Mathew Goggin (AUS) 72 71 67 69, Brendon de Jonge (ZIM) 68 70 68 73, Geoff Ogilvy (AUS) 71 72 67 69, Aron Price (AUS) 73 71 67 68, Jason Scrivener (AUS) 69 71 70 69, Marc Leishman (AUS) 71 71 72 65

280: Gaganjeet Bhullar (IND) 69 72 69 70, Matthew Millar (AUS) 69 70 71 70

281: Nathan Holman (AUS) 68 65 70 78

282: Maximilian Kieffer (GER) 67 72 72 71, Gareth Paddison (NZL) 74 69 72 67, Peter Senior (AUS) 74 68 71 69, Michael Hendry (NZL) 72 69 71 70

283: Peter Fowler (AUS) 73 71 71 68, Scott Strange (AUS) 73 71 68 71

284: Michael Long (NZL) 75 69 69 71, Mark Brown (NZL) 71 70 71 72, Anthony Brown (AUS) 68 73 75 68, Jason Norris (AUS) 69 69 73 73, Jin Jeong (KOR) 73 70 71 70, Peter O’Malley (AUS) 68 71 74 71, Stephen Leaney (AUS) 68 74 70 72

285: Ashley Hall (AUS) 72 72 68 73, Bryden MacPherson (AUS) 69 73 72 71, Clint Rice (AUS) 69 71 71 74, Peter Wilson (AUS) 69 71 72 73, Rohan Blizard (AUS) 71 70 71 73

286: Terry Pilkadaris (AUS) 69 72 73 72, Nick Flanagan (AUS) 73 69 71 73, Aaron Pike (AUS) 73 71 68 74, Matthew Giles (AUS) 74 71 70 71, Cameron Percy (AUS) 73 71 69 73

287: Matthew Guyatt (AUS) 71 70 70 76, Daniel Fox (AUS) 71 69 73 74, Bradley Lamb (AUS) 71 70 72 74, Mahal Pearce (NZL) 74 71 72 70

288: Craig Hancock (AUS) 69 73 73 73, Brody Ninyette (AUS) 68 70 70 80, Andrew Kelly (AUS) 72 71 70 75, Cheng Tsung Pan (a-CHN) 70 73 71 74, Josh Geary (NZL) 70 72 70 76, Max McCardle (AUS) 72 73 75 68, Michael Wright (AUS) 72 71 71 74, Brad Shilton (NZL) 72 71 76 69

289: Anthony Summers (AUS) 72 70 75 72, Peter Cooke (AUS) 70 73 70 76, Nick O’Hern (AUS) 78 67 72 72

290: Quinton Howe (AUS) 72 73 68 77

291: Nick Gillespie (NZL) 73 71 75 72, Brett Rankin (AUS) 68 71 74 78

292: Steven Jeffress (AUS) 76 69 73 74, Steven Alker (NZL) 72 69 76 75, Stephen Dartnall (AUS) 70 74 76 72, Nathan Green (AUS) 72 73 74 73, Jarrod Lyle (AUS) 72 71 70 79

293: Richard Green (AUS) 74 71 77 71

294: James Nitties (AUS) 70 74 73 77

295: Scott Hend (AUS) 73 70 75 77

298: David McKenzie (AUS) 74 71 74 79