He had scored five goals, five ways in the same game - even strength, power play, shorthanded, penalty shot and empty net. It was such a phenomenal achievement that no one, not even the great Lemieux, had ever conceived it could happen in an NHL game.
"It wasn't something you thought about - five goals, five ways," Lemieux said. "I was very proud of the five-goal game, but we were just trying to win a hockey game and get ourselves into playoff position. I didn't realize what had happened until after the game."
Now, however, on the 100-year anniversary of the NHL, everyone realizes how unique - and truly great - the moment was.
The league's website, nhl.com, recently conducted a two-month, bracket-style tournament of fan balloting to determine the greatest moment in a century of NHL hockey. The two finalists were Lemieux's "five goals, five ways" and Bobby Orr's "flying goal" that won the 1970 Stanley Cup for the Boston Bruins.
Finally, on Saturday night, at the 2017 Scotiabank NHL100 Classic in Ottawa, it was announced that Lemieux's performance - five goals, five ways -- had won the voting as the greatest moment in NHL history.
"There have been a lot of great plays in 100 years," said Lemieux, taken aback when he was first informed by league officials. "This is something very special from the fans. I feel very honored."
Voting at nhl.com began in mid-October with 64 moments nominated by a panel of national broadcasters from Canada and the U.S.
Lemieux's memorable goal-fest came in an 8-6 victory over the New Jersey Devils on New Year's Eve 1988 at Pittsburgh's Civic Arena.
In the waning moments of that game, with the Penguins clinging to a 7-6 lead and the Devils' goaltender pulled, Penguins winger Jay Caufield collected the puck in the neutral zone and sent a pass to Lemieux.
"I didn't know what was happening (about five goals, five ways)," Caufield said. "I don't know that Mario knew. We'd seen him do some unbelievable things. This was just another one. What he did each and every night, it was always amazing."
The "five goals, five ways" achievement came in the midst of Lemieux's most productive season ever, statistically speaking. He led the league with career highs of 85 goals and 199 points, won the Art Ross Trophy and helped the Penguins to their first playoff berth since 1982, a span of seven years.
But he also made history - all-time NHL history
"I want to thank the fans for this tremendous honor," Lemieux said. "There have been so many great plays in 100 years of NHL hockey. So many great players. To be chosen as having the greatest moment is something I'll always remember."