Goalkeeper Jonas Gustavsson produced 24 saves and Linus Omark scored a goal and an assist to secure the Swedes' win.
"We played a really good game, really tight, and didn't make many mistakes today," said Swedish head coach Bengt-Ake Gustafsson.
Sweden looked more focused from the start and went into the lead through New Jersey Devils rearguard Johnny Oduya, who fired the puck home from just inside the blue line 5:47 into the match.
"We got a very important first goal and the pressure was on them after that. I'm very pleased with what the team did today, and I'm looking forward to the rest of the tournament."
Switzerland poured forward in attack looking for an equaliser but the Swedes defended stoutly, stifling the hosts attacks into fruitless long-range shots and kept their net clean.
Johan Harju made it 2-0 for Sweden at 24:59 redirecting Omark's shot into the net on powerplay.
Omark added his goal 6:41 into the third, while Johan Andersson made it 4-0 for Sweden at 55:06. Gustavsson lost a shutout at 56:44 when Romano Lemm netted the hosts' consolation goal.
Switzerland, however, still have a chance to stay in the race for the title if they beat the United States in regular time on Monday.
The reigning champions Russia, who already won their qualifying Group E, notched a 6-1 win over Latvia, who needed at least a point for a pass into play-offs.
But Russia offered no mercy to their Baltic neighbours as Anton Kuryanov put them
into the lead on powerplay at 11:43, while Alexei Tereshchenko and Oleg Tverdovsky added one apiece in the second before Kuryanov made it 4-0 with his second of the match.
Herberts Vasiljevs reduced the arrears but Alexander Frolov restored Russia's four-goal lead before Tverdovsky netted his second of the match 6:28 into the third to round off scoring.
In Group F, Canada, who already been given a pass into the quarter-finals, recorded their fifth consecutive win at the event beating 5-1 Norway to dash the Scandinavians' tiny hopes of a place in the play-offs.
Matthew Lombardi lifted Canada 1-0 up 4:40 into the game on powerplay but Norway levelled eight minutes later through Mats Zuccarello Aasen, who also scored during Norway one-man advantage.
Nashville Predators defender Dan Hamhuis restored Canada's lead with 2:52 remaining in the period, while Steve Stamkos of Tampa Bay Lightning clinched the lead in the championship goalscorers table with his fifth goal here so far at 18:03.
In the second Ottawa Senators' Jason Spezza and Drew Doughty of Los Angeles Kings added one apiece to secure Canada's win.
In the late Group F match Czech Republic beat Belarus 3-0 to avoid playing with champions Russia in the quarter-finals.
The opponents were battling tough at the ice of Zurich-Kloten arena but failed to break the deadlock until 30:02, when Petr Cajanek scored a shorthanded goal.
Patrick Elias of New Jersey Devils increased the Czechs' lead with a powerplay goal with 57sec remaining before the second break, while Cajanek scored his second at 55:52.