By Elizabeth Dilts and Fiona Ortiz

NEW YORK (Reuters) - Golf wunderkind Jordan Spieth's resounding win at the Masters golf tournament on Sunday not only will boost his personal sponsorship deals but could give the sport a much-needed jolt.

Spieth had already amassed an impressive list of endorsements before the Masters, including AT&T Inc, Rolex and Under Armour Inc, which signed a multi-year deal with Spieth in January.

Under Armour did not return calls for comment.

Now that he's considered one of the top golfers in the world, Spieth can be expected to add two or three large sponsors this year, said Matt Delzell, managing director of The Marketing Arm, a promotions and marketing agency.

The 21-year-old Texas native tied Tiger Woods' record of finishing the course 18 under par and became the second-youngest golfer to win the prestigious tournament at Augusta National, sending final round TV ratings up 23 percent over last year's final, according to Nielsen data provided by CBS Sports.

When Bubba Watson won the green jacket at the 2014 Masters, he played to the smallest TV viewing audience for the event in more than 25 years - about 8.5 million viewers, according to Nielsen. Back in 1997, Tiger Woods won his first Masters in front of nearly 16 million TV viewers.

"When Tiger faded, the interest in golf began to fade," said Rob Prazmark, president of 21 Sports, a Connecticut-based entertainment marketing company. "Spieth could be the next great inspiration."

However, Spieth, who is now ranked second in the world according to the official world golf ranking website, does not have name recognition. Last week, before his Masters triumph, less than 20 percent of Americans knew who he was, according to Repucom, a sports and entertainment analytics company.

That could now change, sports marketing insiders said, if not overnight then certainly if he continues to chalk up wins.

While golf's popularity has been declining in recent years,

the U.S. is the biggest golfing market in the world and is especially popular among households with an income of more than $100,000 per year. Golf sponsorships remain an important marketing tool for brands trying to reach affluent people. Golf's most marketable celebrity, Rory McIlroy, has sponsorship deals that total more than $40 million a year.

Two likely areas in which Spieth will seek sponsors, Delzell said, are the financial services industry and high tech, where he could promote an edgy accessory that appeals to a younger audience.

Spieth has moved up the list of attractive celebrity sponsors, but companies will watch for two possible pitfalls, experts said. If he fails to consistently win more big tournaments, Spieth's name recognition could dwindle. Such a fate could also befall him if he gets embroiled in any bad-boy antics.

"Golf needs a hero," said Jason Maloni, head of the public relations firm Levick's sports and entertainment team. "(Spieth is) still a ways away from icon status."

(Reporting By Elizabeth Dilts in New York and Fiona Ortiz in Chicago; Editing by Bernard Orr)