Toronto committed a boo-boo Monday night, blowing a home game to an easy opponent.
"There is no explanation for coughing up the puck like we did," Toronto coach Roger Neilson said after the Maple Leafs dropped a 5-4 decision to the Pittsburg Penguins.
Toronto scored the first three goals, fell behind 4-3 and tied the game in the last minute - only one lose.
In the Adams Division, Toronto can't afford to lose even difficult games if it hopes to compete with Boston and Buffalo.
"We took the game too easy and maybe figured our win over Pittsburgh last Friday would make it easier tonight," said Neilson.
Defenseman Borje Salming lost the puck with 32 seconds left and Blair Chapman blasted a 25-foot shot past goalie Mike Palmateer.
"I knew Salming was going to pass and I caught him flat-footed," Chapman said. "The puck hit him in the hip and I saw it fall in front of me. There was no way I was going to blow that one.
"I thought it hit the post and went out but couldn't believe it when it went the other way - after some of the chances I've missed this year."
Darryl Sittler, Jack Valiquette and Lanny McDonald opened the scoring for Toronto but Greg Malone, Pete Mahovolich and Jean Pronovost tied the score before Pronovost scored again for a 4-3 lead, McDonald tied the game again with 54 seconds left.
In exhibition games, the Philadelphia Flyers topped Pardubice of Czechoslovakia, 6-1, and the New York Rangers rallied to tie Kladno of Czechoslovakia, 4-4.
In the WHA, Winnipeg blasted Quebec, 9-4, and Birmingham topped the Soviet All-Stars, 6-1.