Yang Yong-eun celebrates after sinking a putt on the 18th hole in the final round of the 2009 PGA Championship at Hazeltine National Golf Club in Chaska, Minnesota. (REUTERS)

CHASKA, Minnesota (Reuters) — Yang Yong-eun's landmark victory at the PGA Championship, where he deprived Tiger Woods of a widely expected 15th major title, highlighted the modern game's remarkable strength in player depth.

The 37-year-old South Korean became the first Asian male to win one of golf's four grand slam events, and he did so after going into last week ranked a lowly 110th in the world.

Yang's stunning breakthrough at a blustery Hazeltine National on Sunday capped an unusual season for the majors with none of the game's big guns going on to triumph.

Argentina's Angel Cabrera clinched the Masters in April ranked 69th, Lucas Glover landed the US Open at Bethpage Black when number 71, while fellow American Stewart Cink (33rd) lifted the Claret Jug at last month's British Open.

It was the first time since official rankings were launched in 1986 that players outside the top 30 had won four consecutive major titles.

World number one Woods, comfortably the best player of his generation, ended his 2009 campaign without a single major victory for only the fourth time in his professional career.

He had previously suffered barren seasons in the majors in 1998, 2003 and 2004 – all years when he was undergoing a swing change.

What made Yang's three-stroke victory at Hazeltine notable was that he triumphed when all the signs had pointed to a Woods victory, the American having won all 14 of his majors when leading after the third round.

On top of that, Woods had not lost any tournament worldwide in nine years when leading after 54 holes by two shots, his cushion going into the final round at Hazeltine.

On closer inspection, though, Yang's world ranking last week belied his true ability.

He already had five Japan Tour victories and two Korean titles on his resume, and memorably held off Woods to win the 2007 European Tour's Champions tournament in China.

Having twice been forced to come through the PGA Tour's qualifying school, Yang claimed his first victory on the ultra-competitive US circuit at the Honda Classic in March.

''If you look at him as a player overall, he's always been a wonderful ball-striker,'' Woods said after closing with a three-over-par 75 at Hazeltine to finish second.

''I think the only thing that's really held him back was the flat stick (putter).''

Yang's ice-cool display on Sunday came as no surprise to Woods who in recent years has pinpointed the depth in the men's professional game.

''The (PGA) Tour is so deep now and the margin between a player who is just barely on the Tour at 125 (in the money list) to some of the top players, it's not that big any more,'' he said. ''It's very small.

''Guys have access to video cameras and technology has certainly helped a lot. We're so much better at getting the right ball, the right equipment that fits you and your swing.

''And the guys have gotten so much more efficient at shooting better scores.''