For the Phoenix Coyotes, that was Mikkel Boedker, the 2008 first-round pick who scored overtime goals in back-to-back games. For the Nashville Predators, it was defenseman Kevin Klein, who emerged from the sizable shadows of teammates Shea Weber and Ryan Suter to score and stop goals.
We don't know who the surprise player of this conference semifinal series might be, but we know there's no lacking in star power.
For Nashville and Phoenix, that starts in net, as the Predators' Pekka Rinne was a Vezina Trophy finalist and kept his strong play going into the first round against the Red Wings. The Coyotes' Mike Smith likely wasn't far behind earning Vezina consideration himself, and he raised his game even higher in the playoffs. Despite facing nearly 100 more shots than Chicago's goalies, he stopped almost everything that came his way.
Each team also has known quantities up front. The Coyotes' Ray Whitney, Radim Vrbata and Shane Doan all are capable of big things with the puck, as are the Predators' Mike Fisher, Sergei Kostitsyn and Alexander Radulov.
Defensively, Weber and Suter are Norris Trophy-caliber players, but the Coyotes' Keith Yandle isn't far behind.
If the players we know step up their games, the ones we don't could make this series extra special.
Of the four Western Conference teams to advance, none scored more goals than the Coyotes. Nine different forwards had at least a goal, tied for second-most in the postseason.
The biggest surprise might have been Mikkel Boedker, who had just 11 goals in 82 regular-season games, but scored in overtime in Games 3 and 4 in the first round.
Antoine Vermette led the team with four goals, and bottom-six forwards Gilbert Brule and Taylor Pyatt each had a pair of goals.
They picked up the slack as leading scorers Ray Whitney, Shane Doan and Radim Vrbata combined for just two goals and four assists.
Martin Hanzal could help. He scored in overtime to win Game 1, but missed Games 3, 4 and 5 with a lower-body injury. He returned in Game 6 between Whitney and Vrbata, and provides a big net-front presence as well as strong faceoff skills.
Vermette centered Boedker and Doan, and scored a big insurance goal midway through the third period of Game 6.
Rookie Gabriel Bourque was among the biggest surprises of the first round, scoring three goals in five games, including the winner in a two-goal outing in Game 1. He also scored the first goal of Game 4, 1:55 into the third period, starting the Predators en route to a 3-1 win.
Linemates David Legwand and Alexander Radulov also had big roles in the offense, combining for three goals and six assists. As a trio, the line was a plus-15.
Their production offset the top line of Sergei Kostitsyn, Mike Fisher and Martin Erat, which had just one goal.
Andrei Kostitsyn matched his brother with one goal playing on a third line with Nick Spaling and Patrick Hornqvist. Hornqvist, who had 27 goals in the regular season, still is looking for his first goal of the 2012 playoffs.
Paul Gaustad anchors a fourth line that is used to shut down the opposition's best lines. Gaustad also is used for big faceoffs -- he won 55.2 percent in the first round.
In his first full NHL season, Oliver Ekman-Larsson has emerged as the Coyotes' best defenseman. The player nicknamed "Harry," for his perceived resemblance to Harry Potter, showed a wizardly control of the puck in the offensive zone, opening Game 6 with a power-play goal and adding an assist. And despite playing an average of 26:31 per game against the high-powered Blackhawks, he was just a minus-3.
Keith Yandle and Derek Morris form the team's top pairing and see most of the hard minutes. Yandle tied for the team lead with five points -- all assists -- and was a plus-5, while Morris was a plus-3.
Rostislav Klesla, David Schlemko, Adrian Aucoin and Michael Rozsival -- if healthy -- will fill out the lineup.
The strength of the Predators is their defense, which in the first round both provided and prevented offense.
Team captain Shea Weber had two goals and a team-high 18 shots on goal. He also was a plus-1 while skating an average of 27:44 per game.
The big surprise was Kevin Klein, who had two goals and an assist in the series, including the winning goal in Game 4. He also had a goal in Game 3, and helped preserve the lead with a sliding stick save to deny the Wings' Cory Emmerton in the third period.
Weber and Ryan Suter, and Klein and Roman Josi ate up the majority of the minutes on the blue line. There's also hope Hal Gill returns from the lower-body injury that kept him out of the first round.
Smith got progressively better as the series wore on. After allowing four goals in Game 2, he let in two per game for the next three games, and closed the series with a 39-save shutout. The Coyotes were outshot 241-159 in the series, but outscored the Hawks 17-12.
The Predators held the Wings to just 23.2 shots per game, but most of what got through, Pekka Rinne turned aside. He allowed just nine goals on 160 shots in five games, but only five of those goals came at even strength.
Dave Tippett might be the best in the League at getting the most out of his players. His players stay within the structure, and that's why they were able to take advantage of every opportunity Chicago gave them in the first round.
The Predators executed their defensive assignments in the first round just the way coach Barry Trotz likes them to. His players know that if they aren't responsible in their zone, they won't see much ice time.
The power play keyed the offense in Game 6, but only scored in one other game. The penalty kill, however, nearly was impenetrable. Of the Hawks' 19 extra-man chances, the Coyotes allowed a goal just once, and killed 14 straight over the final four-plus games to close the series.
Nashville advanced based on its even-strength play. They had just two goals on 22 power plays, while their shorthanded unit killed off 19 of 23 Detroit power plays.
The Predators likely will need to improve in both areas to reach the conference finals.
Shane Doan, Coyotes -- The Coyotes captain is in the second round for the first time in his NHL career. He had just one goal in the first round; if he raises his play, it's likely his teammates follow suit.
Mike Fisher, Predators -- Nashville's top-line center had just two assists and a minus-1 rating in the first round. With his skill and playoff experience, he'll be a vital player in the second round.
Coyotes will win if: Goalie Mike Smith continues to stop everything that comes his way, and the Coyotes continue to take advantage of the opposition's mistakes.
Predators will win if: Their special teams play matches their even-strength offensive production, and they continue to keep the opposition far to the outside in the offensive zone.
Contact Adam Kimelman at email@example.com. Follow him on Twitter: @NHLAdamK