Scotland's Marc Warren equalled the lowest score of his European Tour career to set the pace in the Maybank Championship as Masters champion Danny Willett enjoyed a welcome return to form.

Warren carded seven birdies and an eagle in a nine-under-par 63 at Saujana Golf and Country Club, which left him two shots ahead of Thai teenager Phachara Khongwatmai.

Willett, who has struggled for consistent form since claiming his first major title at Augusta National last year, was part of a six-strong group three shots back on six under which included American Peter Uihlein and Hong Kong Open winner Sam Brazel.

Warren, who needed a strong finish to last season to keep his card, birdied four of his first six holes before making the most of a stroke of good luck to eagle the par-five eighth.

"I didn't hit a great tee shot on the eighth, I pulled it left and I was actually on the ninth fairway," admitted the 35-year-old after his first 63 on a par-72 layout.

"It was quite a long way up though so I managed to hit a five wood to about 15 feet and it was a nice bonus after that tee shot.

"My iron play was very good today and recently I have been making a lot of birdies but a lot of mistakes as well. It was nice to get around without a bogey.

"Last week I made 11 birdies in two days and missed the cut so it's just a matter of trying to keep the positive stuff going, making the birdies and cutting out the slack stuff.

"It is a tough golf course, especially with the wind and the heat and everything else, and grainy greens too. If you shoot a score of nine under you're putting really well so I'll take a lot of confidence from today and move on to tomorrow."

Khongwatmai became the youngest ever winner of a professional tournament when he won the Singha Hua Hin Open on the ASEAN PGA Tour at the age of just 14 in 2013.

And the 17-year-old, who qualified for the Open for the second year running by finishing second in Singapore recently, continued to impress with eight birdies and a solitary bogey in his 65.

"I'm very happy," he said. "I didn't think I could shoot seven under. This course is a tough course. One or two under would be good and if I can make the cut, I'll be happy.

"I didn't think too much about making birdies. I wasn't confident of putting the ball, but they all went in."

Just eight weeks before defending his Masters title, Willett carded six birdies in his first bogey-free round since last year's BMW PGA Championship.

"Around a golf course like this you need to be in the fairways to be able to get close to these flags and I rolled in a couple of putts," said Willett, who missed the cut in Abu Dhabi and was 54th in Dubai. "It was relatively stress free for six under, which is always nice.

"It's not been the start I would have wanted to the season with how things have been but we're still doing the same, still working hard, still training hard, not trying to do anything different.

"We're just trying to get the confidence levels up to where they have been and start hitting some good golf shots again. Today was nice because we took what we've been working on to the golf course and played some good stuff."

Former Masters champion Charl Schwartzel recorded a 71 on his return to action following a knee injury, while Lee Westwood could only manage an opening 73.