McCarthy's short-handed goal broke a scoreless tie in the third period and then off the ensuing faceoff at centre Ben Street fired the puck into the net past goalie Ben Scrivens in the Heat's 3-0 win over the Toronto Marlies in American Hockey League action.
"(Assistant coach) Cail MacLean told me they would probably go forward off the draw, so I figured there was no use trying to win it back," said Street.
"I tried to go forward myself and got pretty good wood on it. I got it high enough that he didn't pick up on it. I picked the right club, I guess."
They were the fastest two goals scored by one team in North American professional hockey history, beating the old AHL mark of five seconds and the NHL mark of four seconds.
"You don't see that very often and we were on the right end of it," said head coach Troy Ward, as the Heat (5-1-2) moved into a tie with Lake Erie atop the North Division.
Street, who now has three goals on the year, is happy to get his name into the history books.
"I'll lie and say it went bar-and-in," said Street.
However, it was McCarthy's goal that stood as the winner, coming with teammate Chris Breen in the box.
The former-NHL defenceman, who has not scored a short-handed goal in his professional career, rushed the puck up ice, skating wide on a Marlies (3-2-1) defender before taking the puck to the net and squeezing it through the pads Scrivens, who made 24 saves in the loss.
"It was a huge play by a veteran-type player," said Ward. "There are moments in games where you need to step up and he made a great play at the right time.
"It was the play that will go (unnoticed) in this whole thing and it was the biggest play of the game."
Sven Baertschi added a goal into an empty net.
Abbotsford goaltender Barry Brust made 22 saves for his 17th career AHL shutout and enjoyed witnessing the historic moment from the other end of the ice.
"That was pretty weird and I can definitely sympathize with him," said Brust. "I'm just glad it wasn't me."
Brust was a key member of the penalty kill that was stopped all nine Marlies' power plays. The Heat's PK is now 36 for 37 on the season and has actually outscored the opponent's power play 3-1 this year despite having a rotating defensive group and alternating goalies.
"It's a credit to our coaching," said Brust. "Everybody has a job and knows their job as well as everyone else on the ice's job. It makes it pretty interchangeable.
"It's been a godsend, our penalty kill, because we've been taking stupid penalties."