The English midfielder was a second-half substitute for Mark Warburton’s men as they chased an equaliser against their bitter rivals.
Kenny Miller had given the Ibrox side a 12th-minute lead when he tapped home at the back post after neat play from Josh Windass and James Tavernier, but Celtic got back on level terms through Moussa Dembele before the break and Scott Sinclair made it 2-1 on 70 minutes when he tapped home.
So Forrester was thrown on, alongside Dodoo, to help change the game for Rangers – and they wasted a big opportunity to do just that.
With both men in a 2 v 1 against Erik Sviatchenko in the final 10 minutes, Forrester could have laid Dodoo in for a one-on-one with Craig Gordon, but the winger decided to go it alone, allowing the Celtic defender to recover and clear for a corner:
Dodoo wasn’t happy with his decision, just like the thousands of frustrated Rangers fans inside Ibrox and watching on TVs around the country.
And now Forrester has held his hands up after watching it back and said he made the wrong decision:
Just watched the game back, big mistake by me not slipping in joe. Hold my hands up.Had a lot of chances to get something from the game.?⚪️?
— Harry Forrester (@harry_forrester) January 2, 2017
That will be refreshing for Rangers fans to see a player admit to a mistake, but it’s too late now as the team fell to a 2-1 defeat that leaves them 19 points behind Celtic in the Scottish Premiership table.