Sweden will now advance to the semi-finals and play the early game against Russia on 4 January. Canada-Finland will be the late semi-final.
The 5-0 victory was their 11th straight win over the Czechs at the U20, dating back to December 2002. The Czechs finish in 7th place.
Hugh Alnefelt stopped 23 shots to record the shutout for Sweden, while Nils Hoglander had two goals and an assist to raise his tournament-leading point total to 10.
"We played okay in the first, better in the second, and in the third we shut them down," said Hugo Gustafsson. "It was a tough game playing in front of 8,000 fans mostly cheering against you. But we had better speed, I think, and were always trying to attack."
"We were the underdog in this game, but we never gave up. I'm really proud of how we played," said Czech captain Libor Zabransky. "We played hard and blocked a lot of shots, but we also took too many penalties."
Sweden had the better of play right from the drop of the puck, and along the way they earned three power plays in quick order, nearly five successive minutes with an extra man, including one 30-second period of five-on-three.
Finally, near the end of the last one, they connected when Hoglander knocked in a rebound in the crease after goalie Lukas Dostal couldn’t control a Samuel Fagemo point shot at 13:08.
Two minutes later, with the Czechs on the power play, Dostal made the kind of gaffe you know will wind up on YouTube. The Swedes cleared the puck the length of the ice and Dostal handled it behind his goal. He fanned on the clearing, though, and the puck stopped softly in the crease where Hugo Gustafsson tapped it in the empty cage for the easiest short-handed goal he’ll ever score.
Hoglander wired a low shot in, and the Swedes spent the rest of the period killing the clock, keeping the Czechs to the outside, and allowing precious few decent chances.
Their best scoring chance came early in the third during a Swedish power play. Victor Soderstrom lost the puck at the Czech blue line and Jaromir Pytlik raced in alone on goal. His wrist shot was beautifully gloved by Alnefelt to keep the Czechs scoreless.
The Swedes made it 4-0 at 4:04 of the third when Soderstrom scored on a penalty shot. It was the first Swedish PS goal since Kristian Huselius in December 1996.
Their fifth goal was a thing of beauty. It came on a power after the Czechs failed to clear. Hoglander, Nils Lundkvist, and David Gustafsson made a quick series of passes, Gustafsson finishing the play off with a tap-in.
"It was a relief to get that first goal," Gustafsson said. "I've been getting a lot of chances, so it was nice to finally score."
The Czechs now go home and the Swedes have 48 hours to prepare for Russia.