Boss Jurgen Klopp had kept team selection a secret, despite there being plenty of pre-match talk about Origi getting the nod.
The forward scored against Dortmund as the Anfield outfit drew 1-1 in Germany.
And Origi is quoted as saying: "We were playing a big team and as the striker, I had a big responsibility but I felt the support of everybody from the coach to my teammates and the fans.
"Everyone tried to help me as much as possible and it showed in my performance. I only knew [I was starting] when I saw the teamsheet, which was today."
Picking Origi paid off for Klopp, of course. The forward was able to help out defensively, work hard off the ball and aid Liverpool's plan of keeping things tight against Dortmund.
That's not forgetting the fact Origi scored a precious away goal for the Reds.
The irony, though, is that Daniel Sturridge may well have slotted home the chance Origi missed to double Liverpool's lead.
But no one can always deliver perfection and the 20-year-old did a fine job on Thursday night - especially as he didn't know he was starting until matchday itself.