The England defender was suspended for the fixture after picking up a needless red card in the dead rubber group stage game against RB Leipzig in December.
He therefore didn't travel to Lisbon and watched at home as Pep Guardiola's side ran riot with five goals inside an hour.
Bernardo Silva struck twice, with Riyad Mahrez, Phil Foden and Raheem Sterling also getting in on the act.
And after the game, Walker took to Twitter and Instagram to share the video he had recorded for his colleagues.
The former Spurs right-back was wearing one of his England caps, holding a Champions League Man of the Match trophy and with his silver runners up medal around his neck.
"First and foremost I just want to say sorry I can't beat there tonight cheering you on," Walker said in the video.
"I'll be watching at home. Make sure we get a good victory and a good position going into the second leg.
"I want to change this silver one to a gold one but I feel what we're doing and achieving as a team, this will be the icing on the cake - to end up in a final again and hopefully lift this Champions League.
"All the best tonight lads and I'll see you when you get back."
Walker was integral to City's run to the final in Porto last year, where they were beaten 1-0 courtesy of a Kai Havertz strike just before half-time.
The Premier League champions are favourites for the competition this term and appear to have one foot in the quarter finals after a resounding away victory at the Jose Alvalade Stadium.
While some people could see what Walker's intentions were, many felt his message was a little strange and might not age too well:
😂 Celebrate that Silver medal. That's the closest thing you have to UCL..— Klay Thompson (@Zestgod_47) February 16, 2022
Throw a huge party😂 🤞🏾 https://t.co/miDiIhyZdT
This video when y’all don’t win again? Banger! 😭😭😭😭😭 https://t.co/6lkkeiudnD— bubu. (@nombulelo_booi) February 16, 2022
Can’t wait for this to go around again as soon as City inevitably don’t win the UCL this season. https://t.co/nn9NH9hiJv— JT ⭐️⭐️ (@JT__19) February 16, 2022
I see it’s that time of the year where we have to take Kyle Walker’s phone off him again https://t.co/uXkBzIQmZ2— 🇲🇦 (@omarmcfc01) February 15, 2022
Why’s he wearing his silver medal and holding a motm trophy like he’s won it 😭 https://t.co/NAngudwoVJ— ًً (@jensonj671) February 15, 2022
That losers medal looks unreal on you, mate😮💨 https://t.co/qvHktI1Kdf— billy🏴 (@BillyHoar) February 15, 2022
Walker was hit with a three-game European suspension for his poor challenge on Andre Silva, which was the second time he's been sent off in a City shirt.
UEFA categorised the tackle as "assault", though City have appealed the length of the ban.
Featured Image Credit: Image: Kyle Walker
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