The man he took over from was Northern Ireland's Rory McIlroy, who had held the exalted position for just a fortnight before being usurped by his Ryder Cup team-mate. Their nearest challenger, and the only man within touching distance of them at the top of the rankings, is England's Lee Westwood.
Two weeks beforehand McIlroy had also needed to win to climb to the top; and the tournament in the intervening week was won by Englishman Justin Rose, who by doing so entered the top 10 - giving the UK four of the world's top eight golfers.
And it doesn't end there. With Graeme McDowell in the world's top 20, and the likes of Paul Casey, Ian Poulter, Simon Dyson and Martin Laird not far behind, British golf is enjoying an almost unprecedented era of success.
History tells us that it won't last, so we are celebrating the achievement of Donald and co by looking back at the other purple patches enjoyed by British sporting stars and teams in various sports throughout history.
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European football's greatest prize has seen several periods of domination by individual clubs or clubs from a particular nation. But the only country ever to have brought back the trophy six times in a row is England, with Liverpool (three wins), Nottingham Forest (two wins) and Aston Villa (one win) keeping the European Cup in the country from 1977 to 1982 inclusive. Liverpool added a further win in 1984 to make it seven in eight years.
Golf: The late 1980s and early 1990s
With the exception of Tony Jacklin's brief stint in the limelight, British golfers had been in the shade of their American counterparts for half a century by the middle of the Eighties. That all changed when Sandy Lyle, Nick Faldo and Ian Woosnam - all inspired by the global success of European talisman Seve Ballesteros - established themselves as the best players in the world. Faldo in particular was the clear and undisputed world number one, the six-times Major champion achieving a level of dominance (particularly during 1990 and 1992) that would not be seen until Tiger Woods appeared towards the end of the decade.
Sebastian Coe (centre) and Steve Ovett (left)
It seems amazing now that British athletes could dominate such keenly-contested events as the 800m and 1500m, but the exploits of fierce rivals Seb Coe and Steve Ovett put British runners on top of the world. During one memorable spell in 1981 the pair exchanged the mile world record three times in 10 days. While the pair were at the height of their careers, Steve Cram set new 1500m and mile world records and enhanced the reputation of British running still further.
Olympic sports: The 1908 medal mania
The last Olympics in Beijing were a huge success for Britain as they won 19 gold medals and 47 in total. It was Britain's most successful post-War Games - but it is unrealistic to expect that GB could ever emulate their success at London's first staging of the Games in 1908. On that occasion the British team won an astonishing 146 medals — 56 of which were gold. Of course not as many countries competed in those days, but it was still a remarkable achievement. Particular success was achieved by the British team in the boxing events, where out of a possible 15 medals across the five weight classes, they won all but the middleweight silver medal.
Argentina's Juan Manuel Fangio dominated the early days of F1 in the 1950s - at the expense of one of our greatest ever sportsmen in Stirling Moss, who never won the world championship - but it was British drivers who were on top in the following decade as Graham Hill, Jim Clark, John Surtees and Jackie Stewart brought home eight drivers' titles in 12 seasons from 1962.
Perhaps even more impressive is the success that British engineers have had: every F1 constructors' championship was won by a British team from 1984 to 1998 inclusive, with the Italian team that ended that run (Ferrari) only doing so under the guidance of Mancunian Ross Brawn.
Cricket: England in the late 19th century
Many assume that the Ashes legend was born when England's dominance in the early days of Test cricket came to an end. The reality is rather different: England had in fact won just two and lost five of the first official Test matches in history, all played against Australia - but it was a seven-run defeat, for the first time in front of a home crowd at The Oval in 1882, which sparked the newspaper spoof about the death of English cricket.
From that low point, however, England enjoyed their longest spell of dominance over the Australians to date. England began by winning a three-Test series in Australia, the inaugural contest for the Ashes urn, in the winter of 1882/3 by two Tests to one.
In the following 15 years, they lost just one series in 10 where two or more Tests were played — and beat the only other Test team in existence, South Africa, six times in six encounters.
In the hoopla that surrounded Jonny Wilkinson after his drop-goal secured the World Cup in the autumn of 2003, it was easy to forget that he was merely one man in a fighting unit that had lost just one of its previous 22 matches (that defeat was merely a summer World Cup warm-up against France in Marseille with an experimental team that omitted Wilkinson, skipper Martin Johnson and several other big hitters).
That sequence of victories included wins against the biggest sides in the game, including wins away in Australia and New Zealand; indeed, the team had not lost to a southern hemisphere side since a game against the Springboks in Pretoria in June 2000.