They ended up at the top of the first-round leaderboard Thursday in the Reno-Tahoe Open.
Romero, from Argentina, had seven birdies in a bogey-free round to finish with 14 points and take a one-point lead over Noh in the PGA Tour's first modified Stableford scoring event in in six years.
Noh, a 21-year-old Tour rookie from South Korea, had seven birdies and a bogey in the system that rewards aggressive play. Players receive eight points for double eagle, five for eagle, two for birdie, zero for par, minus-one for bogey and minus-three for double bogey or worse.
Josh Teater, John Mallinger, Ricky Barnes were tied for third with 11 points at Montreux Golf & Country Club. John Daly had six birdies and two bogeys for 10 points to match Hunter Haas, J.J. Henry, Danny Lee and former UCLA star Patrick Cantlay.
Romero, who tied for second in the Memorial in June, won the PGA Tour's 2008 Zurich Classic and also has eight international victories.
''I had a good feeling on the greens and that's why I got the score,'' said Romero, who birdied four of his first six holes and would have shot a 7-under 65 under a traditional stroke-play format.
It was the first time he has played in the Stableford format, which was last used on Tour in 2006 in the final year of The International in Colorado.
''It's unusual to see scores on the board like (plus) 14 or 12 or whatever,'' Romero said through an interpreter, adding that it also was unusual for him to finish a round without a bogey. ''I usually have a lot birdies and bogeys as well. I'm usually very aggressive.''
Organizers of the Reno tournament, played opposite the World Golf Championships' Bridgestone Invitational in Akron, Ohio, won approval from the PGA Tour earlier this year to use the scoring system that is designed to entice players into risky attempts at eagles and birdies.
All four par 5s at the 7,472-yard course on the edge of the Sierra Nevada can potentially be reached in two shots and a few of the par 4s are within driving distance for some players.
Noh, who turned pro in 2007, already has three top-10 finishes in his first full season on Tour. He tied for 15th last week in the Canadian Open, has earned more than $1.2 million and ranks 38th in the FedEx Cup standings.
He originally intended to take the week off to prepare for the PGA Championship, but his new caddie had other ideas.
Michael Bastor, who lives in Denver where the high elevation also causes the ball to travel about 10 percent father and who has caddied for fellow South Koreans Y.E. Yang and Charlie Wi, told Noh his game was well suited for the Stableford format.
''I get a lot of birdies, normally five birdies per round'' Noh said. ''So Mike wanted me to play this week.''
Mallinger was among those buoyed by eagles, holing out with a sand wedge from about 110 yards on the 636-yard, par-5 eighth.
''Just kind of skipped one, hopped one in,'' he said. ''In this format eagles are massive so just jumped me right up the leaderboard.''
Henry, who has three finishes in the top 10 this year and claimed his only Tour victory at the 2009 Buick Open, holed out from 167 yards for a rare 2 on the difficult 429-yard, par-4 12th.
Teater, whose lone win came in the 2009 Utah Championship on the then-Nationwide Tour, had a more traditional eagle on the 616-yard, par-5 18th when he hit his approach shot 262 yards to 13 feet of the pin and dropped the putt.
Haas was among those who felt the sting of the risk-reward setup. He shared the early lead at 12 on the strength of six birdies but bogeyed the difficult par-3 16th and did the same on the par-5 18th when he tried to go for the green with his second shot from 262 yards out and instead found the green-side pond.
Teater, who tied for fourth last week in Canada, said it was hard to compare to his best rounds of the year, including a pair of 64s at the True South Classic in Mississippi – where he tied for ninth on a course with soft greens receptive to approach shots.
''You were in attack mode down there. Here you've got to think a little more. There are a lot of math calculations out there,'' he said. ''Usually you're hitting a 9-iron about 150 and now you're hitting it 165. It's a little bit of adjustment.''