The 26-year-old from Worksop held off the Dane Thomas Bjorn in a thrilling head-to-head in Switzerland to add the Canon European Masters to his Dutch and European Open titles. It is a hat-trick that has earned Westwood just over pounds 500,000 - and with this latest pounds 150,000 cheque he becomes only the 13th player to break through the pounds 3m barrier on the circuit.
Finally coming to terms with the controversial Crans-sur-Sierre greens re-designed by Seve Ballesteros, Westwood shot a closing 65 to Bjorn's 66 to win by two shots.
The two 1997 Ryder Cup team-mates - Westwood will be in Boston for the defence of the trophy later this month, but Bjorn will not - had a better- ball of 60 and were locked together with four holes to play.
When Westwood sank a 40-foot eagle putt on the long 15th he looked to have struck a decisive blow. But Bjorn followed him in from 12 feet for birdie, and they then both birdied the 236-yard 16th.
Unfortunately, it was a mistake that effectively settled it. Bjorn, bunkered off the tee at the 17th, went over the green, chipped eight feet past the hole and missed.
He still sensed a chance to force a play-off on the 405-yard last, but after Westwood had left his long first putt seven feet short Bjorn missed his 12-foot birdie attempt.
With two putts for victory, Westwood took only one to finish on 270 - 14 under par.
Germany's Alex Cejka was third six strokes back and the 46-year-old Scot Sam Torrance, in easily his best display of the season, shared fourth spot with France's Marc Farry.
"That was one of the best days I've ever had on a golf course," said a delighted Westwood. "I don't think you will see two guys play as well for a long time. Thomas should be proud of himself.
"I'm playing very well at the moment and I'm capable of being in contention next week [at the Victor Chandler British Masters at Woburn starting on Thursday] to try to make it four in a row."
Nick Faldo was the last player to have three successive victories - and was also the last to have four, a tour record he shares with Ballesteros.
It was Westwood's 17th professional victory - and, with Montgomerie having also won three times since the start of July, it keeps alive the race to be Europe's No 1, a crown Montgomerie has held for the past six years.
The Scot still leads by nearly pounds 325,000, however, and Westwood admitted: "I'd rather be in his position."
When the former British youth champion made his Ryder Cup debut two years ago he had just two tournament victories to his name, but discovering he could hold his own under the greatest pressure in golf was the making of him.
Within two months of partnering Faldo to two wins at Valderrama he had another three trophies - and last season brought seven more around the world.
A mystery shoulder and arm injury halted his progress just after he finished sixth in the Masters in April - at one point he had led with nine to play - but once that cleared up his form quickly returned.
He shot a closing 63 to win the Dutch Open from five back and then a closing 65 a week later to take the European Open in Dublin as well. He had been seven behind Darren Clarke with a round to go there - and won by three.
This time he did his winning from the front most of the way, although Bjorn did lead with six to play before three-putting the short 13th.
Westwood has, somewhat controversially, decided to skip one of the events which does not count in the Order of Merit race - the Cisco World Match Play at Wentworth next month.
Woods is not expected to return this year either, but there could well still be O'Meara, Montgomerie, the Open champion Paul Lawrie and the young Spaniard Sergio Garcia.Reuse content