Zibanejad scored 10:09 into the extra period Thursday to lead his team to a 1-0 win over Russia and earn Sweden just its second gold medal at the event.
The Ottawa Senators draft pick stole the puck from Nikita Gusev before breaking into the Russian zone and roofing a backhand shot over the blocker of goaltender Andrei Makarov, who finished the game with 57 saves.
"He came in on the breakaway and I knew he was going to score," Sweden's Jeremy Boyce Rotevall said. "He told me this morning he was going to finish this game off."
Zibanejad backed up his prediction by beating a seemingly unstoppable Makarov to give his country its first gold at the tournament since 1981.
"I told (Rotevall) before the overtime too so it was good to get that goal," Zibanejad said. "You have to decide if you want to win this. In the morning, it was a joke, but obviously it's not a joke anymore."
THE GAME, IN PHOTOS (Story continues under slideshow)
"I was waiting for the referee to do something or review it. I couldn't believe it and haven't really believed in it yet," said Ronnberg, who heard that there's a big celebration planned in Stockholm upon the team's arrival back in Sweden. "This is a really big for Sweden. It's really important. We have chased this gold for so many years."
It was the first time the two European nations had met in the world junior gold-medal game since the tournament adopted a playoff format in 1996.
"Zibanejad has had a great week and he's the right guy who scores the final goal as well. It's amazing," Swedish defenceman Oscar Klefbom said. "Russia was good, but we were better. It feels amazing. It's a strong team. I love them. All of them."
Klefbom, named to the tournament's all-star team, said there were pictures of the victorious 1981 team hanging in their dressing room
"Thirty-one years. Oh my God. We have to not think about it during the tournament but it is in your head of course," he said.
Johan Gustafsson made 17 saves in Sweden's net for the shutout.
Sweden dominated the first two periods of the game, outshooting the Russians 17-3 in the first period and 22-1 in the second. Despite the lopsided advantage, the Swedes couldn't figure out a way to solve Makarov.
Russian coach Valeri Bragin decided to go with Makarov in net instead of Andrei Vasilevski, who stopped 44-of-49 shots he faced before being pulled in Russia's 6-5 semifinal win over Canada on Tuesday.
"That was a very hard game with a lot of emotion spent," Bragin said through an interpreter after the loss. "The team was tired a bit."
In Makarov's only other start of the tournament, he made 31 saves to lead Russia to a 3-1 preliminary-round win over Slovakia. The 18-year-old goaltender, who plays for the Saskatoon Blades of the Western Hockey League, then turned aside all seven shots he faced in a relief appearance to preserve Russia's win over Canada.
Every time Russian captain Yevgeni Kuznetsov touched the puck throughout the game, he drew a chorus of boos from the decidedly pro-Swedish crowd. Kuznetsov had a hat trick and an assist in Russia's win over Canada.
Kuznetsov was the tournament MVP and the top forward. He also made the event's all-star team at forward along with Sweden's Max Friberg as well as Finland's Mikael Granlund.
"It's nice but we lose the final, so it doesn't matter really," Kuznetsov said through an interpreter. "It's difficult to say anything because the shot clock after two periods was something like 37-5, so if we win it was unfair according to way the game went. I like the way our team played through the whole tournament. We lose the final, but life is going on."
Czech goalie Petr Mrazek also made the all-star team along with Canada's Brandon Gormley and Klefbom on defence. Gormley was named top defenceman, while Mrazek was selected as the best goalie.
Makarov was called upon to make several nice saves in the opening period to keep Russia in the game. After being in the right position to thwart a wraparound scoring chance by Swedish forward Rickard Rakell, Makarov stuck out his left pad to stop a shot that was tipped on net in the slot by Joakim Nordstrom.
Sweden built up a 12-0 advantage on the shot clock before Russian forward Nail Yakupov finally directed a weak backhand on net at 12:34 of the opening period.
A short time later, Gustafsson had to be sharp to make a paddle save to turn aside a shot by Ignat Zemchenko.
Makarov's best stop in the second period was a pad save on a shot from the slot by Zibanejad.
Just past the four-minute mark of the third period, Rakell intercepted the puck from Grigori Zheldakov in the Russian zone. Rakell then drove towards the net and fired a shot on net that Makarov turned aside before getting taken into his own goal by the Swedish forward's forward momentum.
After being attended to by the Russian trainer, Makarov got back up and continued his solid play to keep Sweden off the scoresheet.
Although he wasn't busy throughout the game, Gustafsson was forced to make a spectacular save with 32.3 seconds left in the third. From the left wing, Kuznetsov made a spinning, backhanded pass over to Gusev, who was driving hard to the net. Gustafsson slid across his crease to get in front Gusev's shot and send the game to overtime.
"This team is something special," Gustafsson said. "We really showed that today that we have so much character in this team. It's hard to describe the feeling right now but it's amazing to stand here with the gold medal with these guys."