Crosby gave Pittsburgh a 4-1 lead at 10:44 of the third period on a 2-on-0 with Guentzel. Crosby has eight points (three goals, five assists) in his past three games.
"Every year is a challenge," Crosby said. "You need so many things to go right to give yourself an opportunity to play in the playoffs. It's not given to you. To see how tight the League is, it's not easy. So, you appreciate those opportunities."
Lee cut it to 4-2 at 17:23, but Brock McGinn scored an empty-net goal 36 seconds later at 17:59 to make it 5-2.
Chara scored his first goal in 109 games with a slap shot at 18:52 to make it 5-3, but Guentzel scored an empty-net goal with 10 seconds left for the 6-3 final.
It was Chara's first goal with New York since Jan. 12, 2001, also at Pittsburgh. The defenseman turned 45 on March 18.
"I'm not going to lie, it's always nice to score a goal in the National Hockey League," Chara said. "Obviously, I had way too many opportunities where I kind of hit a crossbar or post this season. It finally went in, (it's) just too bad it wasn't earlier or a better time in the game. Hopefully, the next one is going to help us win a hockey game."
NOTES:Guentzel had two goals and an assist, and Crosby had two assists in a 5-4 shootout loss at the Islanders on Tuesday. … The Penguins' playoff streak began in 2006-07, when Crosby was in his second season, and forward Evgeni Malkin was a rookie. … Pittsburgh forwards Bryan Rust and Evan Rodrigues each played after leaving the game Tuesday with non-COVID-19 illnesses. Rust had one shot on goal in 18:54 of ice time; Rodrigues had two in 7:35… New York forward Kieffer Bellows had two shots and six hits in 11:31 in his first game since March 31, replacing Oliver Wahlstrom (healthy scratch). Bellows had an illness Tuesday, when Trotz said he originally considered making the change. … The Islanders went 0-for-5 on the power play.