(CNN) -- Teenager Matteo Manassero became the youngest player to win two European Tour events as Rory McIlroy's final-day woes continued at the Malaysian Open on Sunday.
The Italian, who turns 18 on Tuesday, finished on 16 under par to head off Frenchman Gregory Bourdy by one stroke after a closing round of 68 and claim the $415,000 first prize.
Manassero, McIlroy and his fellow early pacesetter Alexander Noren had to play 27 holes after severe rain had wreaked havoc during Saturday's third round.
McIlroy, who let a four-shot advantage slip at last weekend's Masters tournament, squandered a two-shot overnight lead and finished third on 14 under after first completing a 72 and then closing with 69.
Manassero, the 2010 European Tour rookie of the year after his breakthrough win in Spain, was not fazed by the extended period of play as he signed for a 67 in the morning.
In his final round, a stunning shot on the par-five 10th saw the Verona-born starlet find the cup from the center of the fairway.
"I couldn't imagine anything better," the world No. 35 told the European Tour's official web site. "Going back home to celebrate my 18th birthday and my second victory on the European Tour.
"As I always say, I could never have expected to have one win before I was 18, and now I've got two.
"It's a great achievement after just 11 months of professional golf. It's a great achievement for myself and gets me into the majors. I just missed Augusta but playing the other three will be fantastic."
McIlroy, who is ranked ninth in the world, was pleased with his form but was disappointed to miss out on glory a week after he saw his hopes of capturing a first career major deteriorated in Georgia.
"At this moment I'm pretty disappointed but it was a good week," the 21-year-old said. "I started off really well in the tournament. To shoot the scores that I did considering the traveling is a pretty good effort.
"Matteo is fantastic. He is a great talent -- to get two wins on the European Tour before your 18th birthday is pretty special. He is great and we've known he is a great player. He deserves it."
Sweden's Noren and Rafael Cabrera-Bello finished tied for fourth on 13 under, one stroke ahead of Chilean surprise package Felipe Aguilar, ranked 348th in the world.
Simon Dyson of Britain was seventh on 10 under, one shot ahead of Mohammad Siddikur of Bangladesh and two clear of world number one Martin Kaymer.
Germany's Kaymer closed with 72 to be eight under alongside Alejandro Canizares of Spain.
Meanwhile, American rookie Brendan Steele took a one-shot lead into Sunday's final round of the Texas Open as he sought his first victory on the U.S. PGA Tour.
The 28-year-old's seven-under total of 209 put him in front of compatriot Cameron Tringale, who also carded 68 in the third round.
Master runner-up and defending champion Adam Scott was tied for fifth, with the Australian three shots off the pace after a 70 on Saturday.