Who can possibly challenge GSP?

MONTREAL – Ever since Georges St. Pierre lost to Matt Serra in 2007, he’s dominated every opponent who has stood in his way.

He has won a UFC-record 30 consecutive rounds, and of late, not only does he not lose rounds, he doesn't even have close rounds.

In short, St. Pierre has become the most physically dominant champion in the sport, and he's generally ranked as the best pound-for-pound fighter in the world.

But Saturday night’s welterweight championship fight against challenger Josh Koscheck, in St. Pierre's home city of Montreal, closed the last remaining doubt. Opponent after opponent thought that St. Pierre always looked to take the fight to the ground – that he was afraid to stand and trade. Well, the fight answered the question.

St. Pierre (21-2) stood for most of five rounds, completely outclassing Koscheck. St. Pierre jabbed effectively, avoided most of Koscheck’s spots, dominated with speed and movement, and he was able to fight five rounds at a hard pace.

We’ve established that St. Pierre’s got wrestling, he’s got boxing, he’s got kicks, he’s got speed, movement and conditioning.

So, then, the question is this: Who at 170 pounds is going to defeat him? Who is the next fighter who can even be competitive with him?

Koscheck, Jon Fitch, Dan Hardy and Thiago Alves could only survive five rounds, taking various levels of punishment. Serra, B.J. Penn, and Matt Hughes couldn’t even survive, and all were finished. Koscheck, Penn, Serra and Hughes have all lost rematches to the champ.

So who's next?

“Jake Shields is the No. 1 contender,” Dana White said late Saturday night.

Shields (26-4-1) is on a 15-fight winning streak. In recent years, he held the Elite XC welterweight title and Strikeforce middleweight title, never losing either title. When it comes to his strength, using wrestling to set up submissions, he’s one of the best in the world.

“He’s one of my favorite guys I like to see fight,” St. Pierre said minutes after his win Saturday. “He’s a very, what you say, meticulous fighter, a very technical guy, a brilliant submission artist. He’s one of the guys I like to see fight the most. He beat everyone at 170 and 185. He’s amazing.”

Still, Shields struggled in his UFC debut on Oct. 23 against Martin Kampmann, winning a split decision that easily could have gone the other way. He made a major tactical error, deciding to drop 20 pounds in one day to make weight. The end result was Shields finding himself in a fight in which he struggled with fatigue as much as with his opponent.

There are two big issues going into promoting a St. Pierre vs. Shields fight. First, there will be very few fans who believe Shields has a chance to beat St. Pierre, simply because they're looking at each man’s most recent fight.

But looking even deeper, when you try and scout the fight, while it’s not impossible for Shields to win, it would require a major tactical mistake by St. Pierre or a fluke for it to happen.

Shields’ strength is his takedown ability, and once he gets people on the ground, he has a great arsenal of unique submissions. But Koscheck is a better wrestler than Shields, and he only got St. Pierre off his feet once in 25 minutes. And standing, St. Pierre is really in a different league from Shields, who is the rare top fighter whose stand-up is considered questionable. The strategy for St. Pierre seems obvious in that fight, and he would have to go in as a heavy favorite.

While any fight with St. Pierre is going to draw well, there is a big difference between Saturday’s blockbuster and a fight with Shields. From a timing standpoint, it could wind up taking place on April 30, when the UFC debuts at the Rogers Centre in Toronto in what is expected to be the biggest live event in company history. But that decision has not yet been made.

“I would love that,” said St. Pierre, moments after his win. “But it depends on the boss [UFC president Dana White]. It’s up to the UFC. I work for the UFC. I love my job. I think I’m healthy. I have some little bruises, so far with the adrenaline, I feel good. Hopefully I still will. I think I can go back to training in two or three days."

Koscheck marketed himself in the fight as being the “bad guy” – people would want to pay to see him get beat up even if they really didn’t believe he could win. Fans have no such connection to Shields.

Once you get past Shields, the next group of contenders is people St. Pierre has already shut out: Penn and Fitch, who will fight on Feb. 27 in Sydney, Australia. If Fitch wins, he will have won six in a row since his 2008 loss to St. Pierre. In that scenario, Fitch would have clearly earned a title shot with wins over Penn and Alves.

If Penn wins, he would have beaten Hughes and Fitch back to back, and it could be argued that he also would have earned a title shot.

Fitch has said he’s found a weakness to exploit in GSP's game, but if there is one, his teammate Koscheck came nowhere close to unlocking that mystery.

After that, you’ve got Carlos Condit, who St. Pierre has never faced. Condit will face Chris Lytle in Australia. Few would give him much of a chance in that fight to do little more than survive. And there’s always the specter of the most-talked about opponent, Anderson Silva, the middleweight champion who has never lost in the UFC. It would be a battle of the consensus top two pound-for-pound fighters in the sport.

When asked, St. Pierre gave basically the same answer he’s given for years. He does not want to be a fighter who messes with his weight. When he is big enough physically to move to middleweight, he will make the move and stay there.

“I don’t want to jump up and down weight classes,” said St. Pierre, whose win on Saturday was his 15th in the UFC. “Right now I’m 189-190 pounds [his natural body weight],” he said. “About a year ago, I was 184. I’ve decided to gain weight and to add muscle to get to 190. I need to be at least 200 pounds to be a middleweight. The guys I train with who are middleweights are all 215, 210 pounds. I haven’t considered the question yet. A lot of people throw that question. We’ll see.”