Stefan Mattsson came out firing during Day 1 of the World Series of Poker’s Main Event on Friday. In fact, the 28-year-old Swede was so aggressive that one of his tablemates — three-time WSOP bracelet winner Barry Greenstein — made it a point to ask who he was and where he came from about 40 minutes after the cards went in the air.

„He was calling me the table captain,“ Mattsson recalls with a wide smile. „I was out of position with him to start the day, but I just kept raising every third hand or so and he only called me twice in six hours. He didn’t want to play me. That was kind of cool.“

If Mattsson continues to glide through the levels of the Main Event like he did the last two years and during his first day of action in 2008, his relative unknown status – particularly here in the U.S. – won’t last much longer. Players like Greenstein will simply have to stand up and take notice.

At the end of Day 1A, Mattsson was in third place with 154,275 in chips. By the end of Day 1D he had fallen to 11th place, but he’s only 88,675 behind the leader, Henning Granstad. When he hits the tables for Day 2 action, he’ll already be in much better position after his first day of play this year than the last two years, which both resulted in hefty cashes. In his first Main Event appearance in 2006, Mattsson collected USD 123,699 with a 57th place finish out of 8,773 entrants. Last year in a field of 6,358 players, he was 22nd and took home USD 333,490.

„I really don’t think a lot of players out there can match what I’ve done the last two years,“ says Mattsson, who signed a one year endorsement with Purple Lounge last summer. „Those were two of the biggest fields ever – by far. I’m not sure there are many players who can say they came in the Top 60 both years.“

As Mattsson says these words he is sitting in one of the WSOP player lounges on Sunday evening, sipping a Corona and killing time before he swings back into action on Tuesday. He’s not being cocky when he speaks about the his success in the Main Event. It’s more a sure confidence. It’s also the plain and simple truth.

Asked why he hasn’t received the recognition that he probably deserves, Mattsson shrugs his shoulders.

„I don’t know,“ he says. „Everybody knows me in Sweden, but I still don’t think I get the kind of attention that a lot of other players do, even back home.“

He tells the story of how all of his friends wanted to wager on him with the European bookmakers to be the highest finishing Scandinavian at the Main Event this year. Except there was one problem. Mattsson didn’t even make the list of choices. He ventures to guess that maybe the lack of attention he garners is due to his low-key nature.

„I don’t like to react too much or make a lot of faces at the table, win or lose, mostly because I have a lot of respect for the other players at the table,“ he explains. „Maybe that’s what it is. Maybe I just don’t make for good TV.„

While he may not be Daniel Negreanu when the ESPN camera lights are on him, Mattsson has managed to shine brightly in other ways at the poker table. He followed up his second straight WSOP cash last summer by taking 41st place (USD 17,156) at the European Poker Tour’s Barcelona Open. In May, he cashed in for a career-best USD 342,989 with a runner-up finish at the World Poker Tour’s Spanish Championship. Since turning pro in 2004, he has earned a more than decent living with USD 829,639 in winnings.

Now, he’s looking to add to that total with a third-straight Main Event cash.

„I like my chances when I get into a tournament with good structure,“ he says. „When I’m in an event that I’m comfortable with, I can read the table and get in a flow. Then I really think I become a threat.“

That’s precisely what happened on Thursday at the Main Event. Mattsson sat down out of position with Greenstein, but played his usual aggressive style. Greenstein – a man with more than USD 6.5 million in career earnings – quickly realized the caliber of player he was up against and didn’t want any part of Mattsson.

At one point the ESPN cameras visited the table to get some footage of Greenstein, who quickly told them they should be filming Mattsson, since he was the real aggressor.

„But I think he jinxed me because while the cameras were there I took a pretty bad beat,“ Mattsson says with a laugh as he recalled raising with a set of 4s under the gun, only to lose to a set of 6s.

After the dinner break, Mattsson was moved to a different table and that’s when he really began to make some noise. Within the first two hours of Level 4, he had bounced three different players out of the eighth spot. Remember that „flow“ Mattsson was talking about? This was a classic case of it.

„Every hand I raised, everyone else just folded,“ he says with a sly smile. „That’s a great feeling. They were really afraid of me. When it gets like that, you can do whatever you want at the table. I love it when that happens.“

It’s something that has happened often for Mattsson at the Main Event, and something that he has a difficult time explaining.

„My friends and I laugh about it all the time; I have no idea what it is,“ he says of his prosperity in the world’s biggest poker event. „And my friends are all real high-stakes cash players. They’re really amazed at what I’ve been able to accomplish [at the Main Event].“

Mattsson arrived in Las Vegas in late June and played just one other event at the WSOP, the USD 5,000 No Limit Hold’em Six-Handed tournament where he failed to cash. Other than that, he’s played a few cash games along the Strip and entered some tournaments at the Palazzo and Bellagio, all while keeping his primary focus on the Main Event.

As Mattsson finished off his Corona, he was handed the 2008 Main Event payout structure, which had just been released an hour earlier. He grabbed the sheet with excitement and raised his brow when he saw the figures. With a 6,844 entrants, the total prize pool is a whopping USD 64,333,600 with USD 9.1 million going to first place.

„I like it,“ he says without taking his wide-eyes off the sheet. „With a [prize pool] like this, a 22nd place this year will pay a lot more than it did last year. But I’m shooting to do even better than 22nd this year. If I keep playing like I have been, there’s no reason why I shouldn’t do better.“

Once again, the words may sound brash, but Mattsson doesn’t even come close to being self-indulgent. In fact, on Sunday night he looked like a kid on Spring Break, having just returned from a giant pool party at the Hard Rock Café. He was looking forward to meeting some friends for dinner and then going out and, of course, playing a little poker.

And when he did sit down at a cash game that night or enter a tournament at the Bellagio, you can bet that the other players probably didn’t recognize him by face.

That, however, could be something that will change in the very near future.

„I hope so,“ he says. „If I keep winning, it will tough for me not to be noticed.“