LET: Lydia Ko fires closing 65 to claim five-shot win at Aramco Saudi Ladies International

Lydia Ko cruised to a five-shot victory at the Aramco Saudi Ladies International as Atthaya Thitikul wrapped up the Race to Costa Del Sol title.

After equalling the course record with a 63 on Saturday to open up a four-stroke advantage, Ko's march to the title was rarely in doubt as she closed with a classy final-round 65 to post a winning score of 23 under par.

The New Zealander followed birdies at the first, fifth and seventh with an eagle at the ninth which took her to the turn in 31, a shot better than closest rival Thitikul could manage.

Ko fired a 65 on the final day

Ko picked up two more shots on the back nine to effectively render the remainder of the round as a procession, and the 24-year-old was content to grind out five closing pars to finish five ahead of Ladies European Tour rookie Thitikul.

"When I was out there, I was just trying to play the best golf that I can," said Ko, whose last win in a regular-season event on the LET was back in February, 2016.

"I knew a lot of the top names were playing really well and this is a golf course where there's a fair amount of birdies, so I was just trying to have my fair share of them and have fun out there.

"It helps when you're going into the final round with a four-shot cushion, you could shoot the same score as others, but you have those shots from the last three days.

"I birdied the first hole and holed two really good putts for par on two and three which really set the momentum up, and from there I tried not to look back and just go forward."

While Thitikul was unable to chase down the two-time major winner, she did have the consolation of finishing outright runner-up which guaranteed her place as the youngest winner of the Order of Merit in LET history.

Atthaya Thitikul was crowned Race to Costa Del Sol champion

"It's an honour and it's a really amazing feeling to win the Race to Costa del Sol this year in my rookie season as well, words can't really describe it," said the 18-year-old Thai star, twice a winner on the LET this season.

"I just did my best out there today with every single shot, but Lydia was absolutely brilliant, I learned a lot from her today.

"Lydia has one of the best short games ever, her putting was brilliant, and every approach shot she played this week, I can definitely learn to get better from her."

Thitikul's spirited 66 was enough for her to finish five shots ahead of Solheim Cup star Carlota Ciganda and England's Alice Hewson, with Olivia Cowan and Whitney Hillier rounding off the top five.