Final round leaderboard:
-14 T Bjorn (Den) -10 A Quiros (Spa) -9 R Cabrero-Bello (Spa), M Brier (Aut) -8 D Howell (Eng) -6 T Aiken (SA), S Hansen (Den), R Karlsson (Swe)
Selected others: -5 S Garcia (Spa), R Finch (Eng) -4 D Clarke (NI), O Wilson (Eng) -2 M Kaymer (Ger)
Bjorn celebrates his 40th birthday on 18 February
Dane Thomas Bjorn showed no sign of nerves as he shot a three-under-par 69 to win the Qatar Masters by four shots.
The Ryder Cup vice-captain, 39, led by one overnight and parred the first 14 holes before birdies at 15, 16 and 18 sealed his 11th European Tour title.
Spaniard Alvaro Quiros posted a four-under 68 to finish second on 10 under.
Lee Westwood, who missed the cut, remains world number one after Martin Kaymer - who needed a top-two finish to depose him - ended in a tie for 28th.
"It's a big win for me and hopefully it can push me on to bigger things now," said Bjorn, who turns 40 on 18 February. "When I play golf like this I know I can be up there with the best in the world.
"I'm going to hit 40 but I'm sure it won't affect my golf too much. I've got to stay fit and healthy but I feel I'm playing well.
"There was a lot riding on today and it's great to get back up into the top 60. I can start looking up rankings again now."
I said a round of 72 would have been difficult to catch in these conditions, and after holing a few putts I knew if I could stick to my gameplan and not make mistakes I would be all right
Bjorn, celebrating his first title since
winning the Portuguese Open
in June 2010, added: "It's been a while so I feel good today. It's nice to get one done finally - and in a strong field.
"I put a new driver in my bag and it gave me another 10 yards, which gave me confidence. I started rolling a few puts in on second day and I think I only had one bogey in the last three rounds.
"I said a round of 72 would have been difficult to catch in these conditions, and after holing a few putts I knew if I could stick to my gameplan and not make mistakes I would be all right.
"I've seen enough in my time to know you've got to go all the way until then end but when I hit the tee shot on the 18th I knew I'd be ok."
The win should secure Bjorn a place in the elite 64-man field for the world match play championship in Arizona later in February.
And it is a huge boost to his hopes of earning a place in this July's Open on the same Sandwich course where he blew a three-shot lead over the closing stretch in 2003.
Bjorn, twice a Ryder Cup vice-captain and current chairman of the Tour's tournament committee, did not have a single bogey in his last 47 holes in Qatar.
Big-hitting Quiros, who finish first and second in the event in the past two years, made a back-nine charge and closed the gap to one as Bjorn reeled off 14 pars in a row in the windy conditions.
I'm not worried about being number one or Tiger going past me and pushing me back to number three as long as I am in the top five on the rankings
But after Quiros three-putted the 470-yard 15th Bjorn hit a brilliant approach there to within four feet of the flag and then added further birdies on the driveable 16th and par-five 18th.
Kaymer, who could only manage a final-round 71, said: "I was in a position to finish in the top 10 I thought but the greens are not my friends here in Qatar.
"Today I played my best golf all week even with a double bogey at the 12th hole. It's just that the putts didn't drop and while it's a disappointing thing on one hand, I am looking forward to going to Dubai and leaving this tournament behind."
The Desert Classic, which starts on Thursday, will see Kaymer, Westwood and Tiger Woods in the field, the first time since October - when Westwood went to number one - that the top three players in the world have contested the same event.
"I'm not worried about being number one or Tiger going past me and pushing me back to number three as long as I am in the top five on the rankings," Kaymer added.
Austrian Markus Brier, who was only one behind Bjorn at the start of the round, could only manage a closing one-over 73 to finish in a tie for third with Spaniard Rafael Cabrero-Bello.
David Howell was the highest-placed Englishman with a final-round 68 to finish outright fifth on eight under par.