Guentzel, a 22-year-old who leads the playoffs with 13 goals, played on a line with Sheary and Sidney Crosby in Game 5.
"No stage is too big for him," Sullivan said. "He has great poise with the puck in all zones. You never see a panic play with him.
"There are so many subtleties to his game that make him the player that he is. And I also think that's what allows him to play with players like Sid. His body of work here from the second half of the season on] and throughout the course of these playoffs speaks for itself."
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Guentzel, who needs one goal to tie Ciccarelli's rookie playoff record, had 33 points (16 goals, 17 assists) in 40 regular-season NHL games.
"He's a gamer," Penguins center Matt Cullen said. "It's fun to see. He doesn't shy away from the battles. He competes. He's just a good player. Look at the kind of kid he is; he's a rink-rat kind of kid. He grew up playing on the outdoor rinks. He just gets the game.
"He knows how to find spots and make plays and he and Sid work very well together. They complement each other and he's so good at finding that soft spot for Sid to find him. It's been huge for us because being able to put him there allows us to balance out our other lines and add more depth on our other lines. I couldn't be happier for him. He's a great kid. It's fun to see him having success."
Guentzel, who grew up in Woodbury, Minnesota, broke the record for most points in one postseason by a United States-born rookie when he got his 19th to pass Jeremy Roenick (18 for the Chicago Blackhawks in 1990) and Joe Mullen (18 for the St. Louis Blues in 1982).
