VIRGINIA WATER, England --
At 20 years, 37 days old, the Italian made amends for letting victory slip at the tournament in 2011. The previous youngest winner was Bernhard Gallacher of Scotland at 20 years, 97 days in 1969.
Manassero has now qualified for next month's U.S. Open, avoiding a 36-hole qualifier on Monday at the Walton Heath course.
"I'm feeling amazing about this win. I also feel really proud and honored to have won the flagship event," he said. "I feel extremely happy. Extremely happy because this place has always had a real special feeling to me and I was in contention in 2011, [but] couldn't do it. That was Luke's (Donald) time, but I'm so proud to win this year."
Khan and Manassero both made birdies for the first three playoff holes before the Italian sealed victory with a par after Khan found the water guarding the green with his approach shot.
Manassero became the youngest winner on tour at 17 years, 188 days when capturing the 2010 Castellon Masters in Spain. He added a second title five months later by winning the 2011 Malaysian Open.
At the 2010 Masters, Manassero became the youngest player to make the cut and he won the Singapore Open last November.
Becoming only the second Italian after Costantino Rocca in 1996 to win at Wentworth earned Manassero $1,012,928 to rise into second place on the Race to Dubai.
"I now have to be obviously looking at the next Ryder Cup and I really want to be there, and that's all I can say," Manassero said. "I can certainly say to you that I feel good in match play because I've done well at the Accenture Match Play Championship, and I've played a lot of match play as an amateur."
Lee Westwood's chances slipped away after shooting a 73 for a share of ninth place. The former No. 1 began the final round one off the lead but raced to two shots ahead with three birdies in succession from this second hole.
However, the Englishman dropped successive shots from the sixth before bogeys at Nos. 11 and 14 and a double bogey at No. 12.
Meanwhile, Sergio Garcia said he will meet Tiger Woods before the June 13th start of the U.S. Open at Merion golf course to apologize in person for his offensive comments directed at the 14-time major champion.
"I've talked with Tiger's manager and asked him if he wanted us to call Tiger," said Garcia, who finished tied for 19th. "Obviously, if he gives us the number or wait for Merion and do it there face to face. But they said they would rather do it there. So, you know, there's nothing else we can do, so we'll wait until we get there and we'll talk.
"It's been a long week and, well, I wasn't really on my best game today. And there have been a lot of emotions going on, and today I kind of felt it a little bit."