Ange Postecoglou revealed it was his personal decision to put Giorgos Giakoumakis after the striker blundered from the spot against Livingston.
Josip Juranovic had converted two out of two for Celtic this season but stepped aside for the Greek forward in the dying minutes of Saturday's goalless draw at Celtic Park.
Giakoumakis' effort was saved by keeper Max Stryjek as Postecoglou's team passed up a chance leapfrog Rangers at the Premiership summit.
The manager stated he'd made the call some time ago to put his summer signing from VVV Venlo on penalties, but he wasn't on the pitch when Juranovic scored from 12 yards against St Johnstone last week.
Postecoglou is confident Giakoumakis will bounce back strongly.
He told BBC Sportsound: "It was my decision, Giakoumakis on penalties. We'd made that decision a couple of games ago, but he wasn't on the pitch when we got the last one so Juranovic took it.
"He was on the pitch and was the designated taker today.
"He'll be disappointed but that's part of being a striker - you get the plaudits when you score, when you don't you've got to pick yourself, get out there again and put the ball in the back of the net.
"I'm sure that's what he'll do."
