'I just like playing in high altitudes, it seems like,' Gronberg said after taking the first-round lead at The International with 13 points in the modified stableford scoring system.
Gronberg gave away three points with a double-bogey on Thursday, but that was his only mistake.
'It's the same format -- high up in the mountains where you hit the ball a long way,' Gronberg said. 'So, obviously, I hit the ball long here, which is kind of a bonus.'
Long hitters didn't necessarily have an advantage during the first round. In fact, only seven of the top 15 players on the leaderboard rank within the PGA TOUR's top 100 in driving distance -- and none is higher than 51st.
Still, the leaderboard was peppered with high scores -- good in the modified Stableford scoring system, which awards points for scores under par and subtracts points for scores over par.
Gronberg is two points better than Stuart Appleby, Stewart Cink, John Senden and 2001 winner Tom Pernice Jr., who each posted 11 during the first round to share second place.
Danny Ellis, Jeff Brehaut and Patrick Sheehan are tied for sixth place with 10 points, one point ahead of a group of seven players led by 1999 champion David Toms and European Tour Order of Merit leader David Howell.
The scores Thursday were outstanding, considering that last year Retief Goosen won with 32 total points -- 16 shy of the record of 48 set by Phil Mickelson in 1997 and matched by Ernie Els in 2000.
Under the modified Stableford scoring system, five points are awarded for eagles and two for birdies, while one point is subtracted for bogeys and three points for double-bogeys or worse.
Eight points are given for double-eagles, although there have been only three recorded in the 20-year history of the event.
Gronberg guessed it might take around 40 points to win this weekend, but said the number could be much lower.
'It depends on the weather,' he said. 'Today, we could not have played in better [conditions]. Maybe the last five or six holes there was wind, and except for that it was beautiful.'
Gronberg played in an early threesome and two-putted for a birdie at the par-5 first to collect his first two points. He nearly aced the fourth on the way to another birdie, then reached six points with a 7-foot birdie putt at the eighth.
The Swede then dropped three points with a double-bogey at the ninth, where he hit a 3-wood into the water.
Making the turn with just three points, Gronberg turned it on with five birdies on the back nine. For the first, he drained a 20-foot birdie putt at the 12th.
'It's strange how you can stand over 3-footers and you're not even hitting the hole, and you can step up on the 20-footer and think, 'I'm going to make this putt,'' Gronberg said.
The biggest difference for Gronberg on the back nine, he said, was his putting.
'The front nine was a little iffy, so I'm happy that I started to roll some good putts in,' Gronberg said.
Els leads a group of 12 players who are tied for 16th place at eight points. Further down the leaderboard, two other previous champions had less-successful rounds.
Goosen opened his title defense with three points and is tied for 65th place, while two-time winner Mickelson had a double-bogey and two bogeys and managed just one point to end tied for 86th.