The England and City defender came on with ten minutes to play after substitute goalkeeper Claudio Bravo was sent-off for a tackle outside his penalty area, subsequently becoming the first substitute goalkeeper to be sent off in the Champions League.
There was a lengthy delay before the 29-year-old took the gloves and came on in place of Riyad Mahrez, but he looked keen to do so early on.
Walker admitted it was a mutual decision for him to don the gloves after Bravo's dismissal.
"It was a bit of both," he said after the match. "I try sometimes to wind up the goalkeepers in training by telling them to catch it and stuff but as I found out tonight, sometimes you need two touches.
"All jokes aside, we came here to get a point or a victory. We knew it would be difficult because they go man-to-man and are in the Champions League for a reason.
"To come away from here with how we ended the game with a draw is a good point and we take that on. Now the focus is on Liverpool for Sunday."
Team mate and fellow full-back Benjamin Mendy described it as a game he will always remember.
The Frenchman told BT Sport 3: "It was a very tough game. We fight until the end and I say thank you to Kyle as it is not easy to take this responsibility to be a goalkeeper and save the free-kick.
"It is one game we will remember in this competition."
Kyle Walker playing in goal wearing Claudio Bravo's shirt is something that will be talked about on City European away trips for generations.
— Sam Lee (@SamLee) November 6, 2019