First round gave us numbers to remember

Aside from Game 7 between the Anaheim Ducks and the Nashville Predators, the first round of the Stanley Cup Playoffs is complete, and it has produced some surprising numbers.
Late leads have been hard to crack, one coach has deployed his checking line in an unusually strict way and rookies played a huge role in one critical series.
Here are five statistical takeaways from the first round:

1. Not great late:There were very few late comebacks in the first round. When trailing going into the third period, only two teams came back to win.
First, the St. Louis Blues were trailing the Chicago Blackhawks 2-1 going into the third period of Game 3, and came back to win 3-2. The New York Islanders were trailing the Florida Panthers 1-0 going into the third period of Game 6, and won 2-1 in the second overtime period.

In the other 29 cases, the team leading after two periods went on to win. That means there has been a 6.5 percent chance of a third-period comeback this postseason, compared to the League average of 14.7 percent in the regular season, when the trailing team came back to win in 139 games in 943 such situations.
Given the near invulnerability of a third-period lead this year, there should be a premium on first-period scoring. However, first-period scoring is down from an average of 1.45 goals in the regular season to 1.20 in the playoffs.
2. Just keep shooting:Normally teams in the lead are outshot by their opponents, especially late in the game. Trailing teams tend to open up, take more risks, and throw just about anything at the net in an attempt to tie the score. Conversely, teams protecting late leads tend to avoid risks, and are willing to yield the puck and pass up on shooting opportunities in order to make orderly line changes and avoid bad turnovers.
That's why it's so unusual the team in the lead actually had the advantage in shot attempts in the Eastern Conference First Round series between the Detroit Red Wings and the Tampa Bay Lightning. Tampa Bay had 12 more shot attempts than Detroit when ahead; the Red Wings had seven more shot attempts when they were in the lead.
The only other team to have more shot attempts than their opponents when leading was the New York Rangers, at plus-2. That's even more unusual, given that the Rangers finished the regular season last in puck possession metrics among playoff teams, and the Pittsburgh Penguins were second to the Los Angeles Kings.

3. Gaustad on center stage:It's not unusual for some coaches to have a single line they rely upon for defensive zone faceoffs. Given the regular cycling of lines, occasional stretches where all the action is in the opposing end and the desire for certain matchups, what's unusual is when that defensive zone usage becomes exclusive.
Such was the case in Nashville, where coach Peter Laviolette used 6-foot-5, 227-pound center Paul Gaustad and wingers Cody Bass and rookie Miikka Salomaki exclusively in the defensive zone. In the first six games of the Predators first-round series against the Anaheim Ducks, Gaustad took 45 draws in the defensive zone, and none in the offensive zone.
4. Huberdeau's debut:In their first-round series against the New York Islanders, the Florida Panthers used a League-high 11 players who had never competed in the playoffs.
Jonathan Huberdeau made the most of his first postseason opportunity, when you look past traditional statistics like goals, points, and plus/minus.
For example, he may have scored one goal, but he led the NHL with 34 shots in the first round, which included a League-leading four deflections or tip-in shots.
Likewise, Huberdreau may have been only a plus-1 in traditional terms, but the Panthers outplayed the Islanders 169 shot attempts to 104 when Huberdeau was on the ice, the widest margin in the League.

5. First-year flair:In the first round, 39 rookies combined for 21 goals and 50 points in 47 games, and 17 of those points were scored in the series between the Chicago Blackhawks and the St. Louis Blues.
Artemi Panarin of the Blackhawks led all rookies with seven points in seven games, followed by Robby Fabbri of the Blues, who scored five points. No other rookie scored more points than St. Louis defenseman Colton Parayko, who scored three.
The Blues also employed rookie Joel Edmundson on the blue line, but the Blackhawks used three rookie defensemen: Erik Gustafsson, Trevor van Riemsdyk and Viktor Svedberg.
Other teams using rookies with success include the Pittsburgh Penguins, who received a combined five goals and nine points from Conor Sheary, Tom Kuhnackl and Bryan Rust; and the New York Islanders, who received two goals and six points from Alan Quine and Ryan Pulock.
For more first-round numbers, go to NHL.com/stats