Heavyweight legend Fedor Emelianenko needed just 48 seconds to knock out Frank Mir on Saturday as business picked up in a hurry at the Bellator Heavyweight Grand Prix tournament.

Emelianenko (37-5, 1 NC), who is widely considered the greatest heavyweight in MMA history, outgunned Mir in a brief and exciting slugfest, which headlined Bellator 198 at Allstate Arena in Rosemont, Illinois. The native of Russia advances to face Chael Sonnen in the semifinals of the eight-man tournament, which will crown a new Bellator heavyweight champion.

"I feel a great joy and happiness," Emelianenko said through a translator. "Thanks God, we won."

The 41-year-old Emelianenko, who lost his Bellator debut to Matt Mitrione last July in a first-round knockout which featured a wild double knockdown, came out just as hungry to mix it up. Mir (18-12), a two-time UFC heavyweight champion, returned to the cage Saturday for his own Bellator debut following a two-year USADA suspension.

After the southpaw Mir dropped Emelianenko to a knee in the opening seconds with an inside leg kick and a left cross, "The Last Emperor" rebounded to fight off a clinch and force a takedown. From there, the fight turned into a brawl on the feet.

Mir, 38, was able to give as good as he received while both fighters traded punches at close range. But as Mir bent at the waist to lean forward, he walked directly into a short left uppercut which dropped him onto his face.

Emelianenko quickly forced the stoppage seconds later with a flurry of punches from behind as referee Mike Beltran waved off the bout at 48 seconds of the opening round.

"That's just what Fedor does and I thought Frank was giving him too much space," Sonnen said. "Frank has great skills but you have to get to those positions. It's not always about who is going to win the fight or who the better fighter even is. It's who is going to win the positions.

"Positions change in a three-round fight constantly and I don't think Frank was getting to the most dominant positions. Being the bigger fighter, I really thought he needed to get his hands on Fedor. He times guys every now and then. He changes that speed and that's what happened to Frank tonight."

Sonnen (31-15-1), who outpointed Quinton "Rampage" Jackson during their first round matchup in January, faced off against Emelianenko inside the cage after the fight. The former UFC middleweight and light heavyweight title challenger added a bit of pro wrestling flare as he cut a promo on the microphone.

"I think the only thing I hate more than being right here in Chicago is being in this ring with you," Sonnen said. "I assure you the next time I am, it will not be for long."

On paper, the Bellator Grand Prix featured a mix of aging recognized names and undersized fighters -- like the May 12 bout between Ryan Bader and Muhammed "King Mo" Lawal -- who are much closer to their prime.

Not only did Saturday's bout play out in about as exciting a manner as possible, it produced a semifinal bout between Emelianenko and Sonnen that is just about the most sexy Bellator could produce in the tournament.

"I will give you this as an athlete, he's very fast," Sonnen said. "We have all known he is powerful. We all know an advantage he has had at heavyweight is being right there in the middle of the road coming in at that 240 or 239 [pound] weight class. When you combine the speed that is going to give him with the power that he possesses, he creates a big problem. But he is next for me. I'm not going to dote on this moment or look at it with any kind of fear as much as an opportunity to bring down Fedor."

While Emelianenko is very much past his prime and would certainly struggle against any elite and full-sized heavyweight, the tournament field allows him an opportunity to produce a thrilling final chapter to his career. Emelianenko also won his first fight on U.S. soil since rallying to knock out Brett Rogers in 2009.