"I've definitely had a few angels in my life," said Mo Martin as she cradled the Ricoh Women's British Open trophy last night.

The 31-year-old American certainly had one looking after her when she played the par-5 18th at Royal Birkdale. From around 250 yards out, she struck a full-blooded 3-wood that pitched just short of the green, raced on, hit the flagstick and set her up with an eagle putt.

It was the shot that won her this tournament. It moved her to the top of the leaderboard, in a three-way tie for first place with Korea's Inbee Park and Shanshan Feng, of China. Both had won majors in the past, while Martin had won nothing more than a handful of minor tour events. But this was her day. This was what her angels wanted.

Martin signed for her round of 72 - matching the best of a blustery final day - and headed for the range. She hoped for a play-off, but the angels fixed up something better.

Park fell back at the par-3 14th, where she went through the green and took three to get down, and Feng made an almost identical mistake at the 16th. Suddenly, Martin was out on her own.

Even so, a birdie for either Park or Feng could still take the tournament into sudden-death. Neither could make it, their last hopes evaporating when they both found the same greenside bunker at the 18th.

Out on the practice ground, diligently going through her swings, Martin made it known she did not want any updates from the course. The first she knew that she was a major champion was when caddie Kyle Morrison scooped her up in a victory embrace.

Martin's grandfather passed away in March. He had reached the grand old age of 102 and he had been her greatest supporter. Not long before he died, he would still attend tournaments sporting his trademark 'Go Mo' badge. Think he might have had a word in the angels' ears?

Martin has certainly overcome a few challenges on her way to the top. Born into a poor Californian family, her father could not afford to pay for her golf lessons, so he bought a copy of Ben Hogan's Five Lessons - The Modern Fundamentals of Golf and taught her himself. He knocked up a practice cage in their yard. When she won a place at college, her grandmother gave her financial support through her first year.

"There are so many amazing people in this world, and not enough is said about them and their good deeds," said Martin. "So many people do things unspoken, unspoken kindnesses. So many people have helped me when I've needed it."

By this stage, there was a touch of Little House of Prairie about Martin's winner's press conference, but only a heart of stone would be unmoved by what came next. Following his death, it had seemed that her grandfather's ranch in the mountains of California would have to be sold, but Martin explained that the £277,887 cheque she picked up last night would make things more secure.

"This win will definitely keep it in the family," she smiled. "We weren't sure we were going to be able to keep the ranch, but it's a very special place for me. It's kind of my sanctuary and it's nice to have all the memories that I have of grandpa. It's an incredible place."

While the hard-bitten golf hacks dabbed their eyes, it was easy to forget that Martin had a few other things going for her yesterday. None was more significant than her well-earned reputation as the straightest hitter on the LPGA Tour. A host of players had predicted that Birkdale would bite back when the wind got up, and it duly did just that. At that point, Martin's precision became a huge asset. She might have been an unlikely winner, but she was certainly not an undeserving one.

Feng finished in second place. Park, forced to be aggressive, went from rough to rough to sand down the last and slipped back to fourth. Norway's Suzann Pettersen, who had earlier carded two double bogeys, redeemed herself with a birdie-birdie finish to share second place with Feng.

Dame Laura Davies, playing in her 30th consecutive Women's British Open at the age of 50 - she was the oldest player in the field - produced a superb 73 to claim a share of ninth, the best finish by a British player.

Vikki Laing, the only Scot to make the cut, shot 80 for 304, an otherwise solid round marred by a quadruple bogey at the 12th. At least Laing could enjoy Martin's success, though, as the pair were college friends - Laing went to Berkeley, Martin to UCLA - just more than a decade ago.