Returning to the top the second time around wasn't nearly as meaningful.
As he walked off the 18th green at the Bay Hill Invitational, where the wrong club at the wrong time cost him a chance to win for the second straight week, Singh didn't even realize he had replaced Tiger Woods at No. 1.
Nor did he care.
'I didn't think I got it back, did I?' he said. 'Well, big deal. I lost the tournament.'
Even during his first reign that lasted 26 weeks, it didn't take Singh long to realize that No. 1 is just a number. More important are the trophies, especially green jackets and claret jugs.
He earned it the first time around by going head-to-head with Woods in the final round of the Deutsche Bank Championship. Tied for the lead with five holes to play, Singh held him off and won by three, ending Woods' five-year run at the top.
'I've worked pretty hard for this,' Singh said that day outside Boston. 'I finally achieved what I wanted to do at the beginning of the year.'
Singh returned to No. 1 in the world on Sunday under entirely different circumstances - he hit a 7-iron into the water on the final hole at Bay Hill to make double bogey and finish two shots behind Kenny Perry.
No wonder Singh cared so little about a title that once meant so much.
'It's all about winning,' Woods said. 'I'm sure he (Singh) feels the same way. If you win a bunch of tournaments each and every year, the rankings will follow.'
The battle for No. 1 probably will continue the rest of the year, certainly for the next month.
Woods has been No. 1 longer than anyone - 336 weeks - since the world rankings began in 1986, and he can get it back this week at The Players Championship.
So can Ernie Els, who hasn't been No. 1 since 1998.
By the end of the year, Phil Mickelson and Retief Goosen might have a chance to reach the pinnacle. Chances are, it will be more meaningful at that point to them than to Singh or Woods.
Mickelson is the best player to have never been No. 1 in the world, with 25 victories and a major last year at the Masters. The ranking is measured over two years, and he hasn't allowed himself much thought on what kind of achievement that would be, other than to say, 'It would be cool.'
Els has been No. 1 on three occasions - for one week after winning the 1997 U.S. Open, then for eight out of nine weeks the following year when Woods started to fall off while changing his swing.
'That's one of the goals - obviously to win major championships, but I'd love to be No. 1,' Els said. 'I'm as close as I've been for a year now. I've been kind of hovering around there for the last year or so.'
Some players have financial incentives built into endorsement contracts that focus around No. 1, and it certainly didn't hurt Singh, particularly when he was referred to as the No. 1 player in a Foot-Joy commercial.
Otherwise, No. 1 is simply a novelty. And it can wear off quickly.
Woods has been dismissing the importance of No. 1 for the last year, perhaps because he was there for so long. He reached the top quicker than anyone, becoming No. 1 for the first time on June 15, 1997, after playing in just 22 professional tournaments, six of them victories. Even then, he was philosophical about the points-based formula that measured three years at the time. Woods had only been playing 10 months.
'Being No. 1 is great,' he said in 1997. 'Right now, I'm No. 1 because I don't have many minuses.'
That there is so much focus on No. 1 shows how strong golf is at the top. Woods, Els and Mickelson have each won two times this year, while Singh finished third at Doral and was tied for second his last two weeks.
The only significance about the world ranking is at No. 50, which qualifies players for the major championships. Graeme McDowell of Northern Ireland was thrilled with his final-round 66 at Bay Hill because it got him into The Players Championship and most likely the Masters.
For now, the great debate is over who's No. 1. Depending on Mickelson, and perhaps Goosen if he shows more consistency, this could be the first year that as many as five players take turns at the top.
The record for most players being ranked No. 1 in a single year is 1997, when Woods (10 weeks), Els (one week), Tom Lehman (one week) and Greg Norman (41 weeks) each were No. 1.
Right now, the biggest battle is between Singh and Woods.
'Vijay has played better the last two years,' Perry said after his victory at Bay Hill. 'It's a toss-up. And they're both fun to watch. It's all about winning with those guys.'
Ultimately, that's all that matters to any of them.
Current World Rankings