Stolen or not, the one-point win secured a finals berth for Malthouse and the Blues.
But he conceded the side would have to play much better than it did in the first half if it was any chance of advancing to the second round of the finals.
The Blues appeared uninspired in the opening half, finding itself trailing by 32 points at half-time and down 49-136 in uncontested possessions.
Malthouse joked he was expecting to be handcuffed after the final siren.
"[I was] looking out for the police, we probably did steal it," Malthouse said.
"But there were probably just enough signs at half time, and then there were enough signs through the third quarter when we had shots, but we just can't miss shots or butcher the ball like we did.
"Once the door opened we were able to keep the pressure on.
"We can't expect to come into finals…[and] not be competitive in that first quarter."
The huge discrepancy in uncontested possessions in the first half was particularly alarming.
Malthouse said it suggested a lack of effort on his players' part but to have come back from a substantial deficit would bode well for the squad.
He insisted the club was never completely out of the game and that the side kept its "flicker" alive.
"To me that's work rate or you tighten up, so there's a few to look at but we'll grow as a side because of this," he said.
"I don't know how far we can go but the simple fact is we're there.
"When there is a flicker, you can't blow it out. You have got to make sure that flicker is still a credible, achievable, positive flicker otherwise it will snuff that out and the game is dead.
"Once we started to run the football and then put scoreboard pressure on, that made Port play differently."
Malthouse wouldn't comment on his team's upcoming final, only that he'd assess it on the team bus, then on the flight home to Melbourne.