Five things learned from Day 6 of World Juniors

Through the four games of group play, the best line for the United States has been Auston Matthews centering Matthew Tkachuk and Colin White.

It wasn't supposed to be that way, but part of having success at the World Junior Championship is the ability to adjust on the fly.

Alexander DeBrincat started the tournament at right wing alongside Matthews and Tkachuk, forming a line of top prospects for the 2016 NHL Draft. Matthews is expected to be the first player picked, and all three players received A ratings from NHL Central Scouting in its November players to watch list.

But DeBrincat sustained an upper-body injury when he fell into the boards during a 1-0 loss to Sweden on Monday, and coach Ron Wilson had to make a change.

He moved Colin White, an Ottawa Senators prospect, into DeBrincat's spot, and that line was dominant in the final two games of the preliminary round, including a 4-1 defeat of Denmark on Thursday.

Matthews and White each had a goal and an assist, and Tkachuk had two assists. That followed their effort in a 10-1 defeat of Switzerland on Wednesday, when they combined for five goals and five assists.

Three of Matthews' U.S.-best four goals have come since White joined the line. Matthews is tied for second at the tournament in goals, and his eight points are tied for third. White and Tkachuk each have seven points.

While the U.S. has gotten goals from 11 of its 20 skaters, it's the top line that will have to continue to lead, starting with a quarterfinal game Saturday against the Czech Republic (1 p.m. ET; NHLN) and continuing with a potential semifinal game against Russia.

Here are five things we learned on the final day of the preliminary round at the World Junior Championship:

Nylander an unknown -- Sweden forward and Toronto Maple Leafs prospect William Nylander missed his third straight game Thursday because of a head injury sustained in the first period of Sweden's first game, Dec. 26 against Switzerland.

Sweden doctor Per Adolf Bergsten on Thursday remained optimistic Nylander could play Saturday against Slovakia (9:30 a.m. ET; NHLN) in the quarterfinals.

"We have said before that hopefully he plays more in this tournament," Bergsten said in a video posted by Postmedia News. "But we take it day-by-day and see how he progresses with his rehabilitation."

Bergsten said he has been in contact with the Maple Leafs and that everyone is on the same page regarding Nylander's potential to return in the tournament.

"I think they have the approach to this as we are," Bergsten said. "That is, if he's able to play he will play. But he must be 100 percent."

Sweden has done fine without Nylander, in part because of the strong play of his younger brother, Alexander Nylander, an A-rated prospect for the 2016 draft. Alexander Nylander leads Sweden with three goals and eight points in four games.

But having William Nylander certainly would be a boost. The 19-year-old leads the American Hockey League with 14 goals and 34 points in 27 games, and he led Sweden with 10 points in seven games at the 2015 WJC.

"Hopefully he plays more in this tournament," Bergsten said. "There is still that hope. He has to move slowly forward."

Flying Finns -- Finland's top line of Jesse Puljujarvi, Patrik Laine and Sebastian Aho continue to dominate the tournament. Puljujarvi had two goals and two assists in Finland's 5-4 win against the Czech Republic. Laine scored the game-winning goal and Aho had two assists.

Puljujarvi, a top prospect for the 2016 NHL Draft, leads the tournament with five goals and 12 points in four games. Aho, a Carolina Hurricanes prospect, is second with nine points. Laine, also a top prospect for the draft, is tied for second with four goals and tied for third with eight points.

Led by its top line Finland has a tournament-best 23 goals, and is 8-for-16 on the power play. It's a big difference from the 2015 WJC when they scored eight goals in five games and went 0-for-20 on the power play.

Woe, Canada -- Canada's 5-2 loss to Sweden on Thursday left it third in Group A and set up a quarterfinal game against host Finland on Saturday (3:30 p.m. ET; NHLN). It's the first time since the 1998 WJC that Canada has lost two games in the preliminary round. Coincidentally, that tournament also was played in Finland.

Canada fans don't want to be reminded of that tournament. A loss to Kazakhstan in the seventh-place game meant Canada finished eighth, its worst-ever result at the WJC. That roster included Colorado Avalanche forward Alex Tanguay, Philadelphia Flyers forward Vincent Lecavalier and Florida Panthers goaltender Roberto Luongo.

The 2016 roster also features future NHL star talent, and four players who returned from the 2015 WJC team that won the gold. But they'll enter the quarterfinals as an underdog. But that appears to be OK to them.

"We're major underdogs," defenseman Joe Hicketts (Detroit Red Wings) told Postmedia News. "We come in and Finland is one of the top teams in the tournament. Especially with a younger group I think when we take that pressure off it might be a little better."

Sweden net issues -- Goaltender Linus Soderstrom finished group play with a tournament-best .942 save percentage and a 1.62 goals-against average that's second. However, the New York Islanders prospect was removed from the 5-2 win against Canada on Thursday with 3:49 remaining in the third period. There was no update from Sweden after the game.

Soderstrom arguably has been the best goaltender in the tournament; the United States players likely would agree after Soderstrom's 46-save shutout against them Monday.

Felix Sandstrom, a Philadelphia Flyers prospect expected to be Sweden's No. 1 goalie, replaced Soderstrom against Canada and stopped the only shot he faced. Sandstrom's only other tournament action came in a nine-save shutout of Denmark on Wednesday.

If Sandstrom has to play in the quarterfinals against Slovakia, Sweden should be OK; Slovakia scored eight goals in four group-play games, second-lowest of the eight teams to advance to the quarterfinals. But Sweden coach Rikard Gronborg likely would feel more comfortable with Soderstrom in net for a potential semifinal game against either Finland or Canada.

Russia remains most special -- Only Switzerland, which next plays in the relegation series, was shorthanded more than Russia during the preliminary round. However, Russia's penalty killing so far has been the best of the WJC.

Russia killed six power plays, including a 5-on-3 advantage for the Czech Republic late in the first period in Russia's 2-1 victory.

In four games Russia has allowed one power-play goal in 15 shorthanded situations, a 93.3-percent success rate.

Russia also has been good with the man-advantage, scoring five times in 14 chances for a 35.7-percent rate that's second to Finland.

While staying out of the box will be key moving forward in the tournament, starting with a quarterfinal game against Denmark on Saturday, the positive is the players shouldn't get concerned if the whistles go against them.

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