It will be staring down at him from the Wembley stands in the form of Jason Thomson, a long-term family friend from the Loanhead area, near Edinburgh, who spent last Sunday captaining Raith Rovers to their last-gasp Ramsdens Cup final win over Rangers.
The Raith skipper is particularly keen to lend his support after a clash with his own wedding prevented many of Flynn's old pals from attending Sheffield United's 2012 playoff final defeat on penalties to Huddersfield. Flynn, meanwhile would love to be part of a similar underdog narrative to the one he managed to locate and enjoy on BBC Alba last weekend.
"I speak to Jason all the time, and we are all buzzing for him," said the 25-year-old. "Although I haven't called this week to see how he has recovered from the celebrations. I thought they played quite well, hit Rangers a few times on the break. I've known him my entire life, I am from just outside Loanhead, so a lot of the boys are coming down this time. I managed to get BBC Alba down here and it was nice to watch it. They were the underdogs too and I will take the same outcome on Sunday."
As demoralising as that 2012 playoff defeat was, Flynn does have some more upbeat memories of cup finals. Having signed for Liverpool's youth team for £50,000 back in 2005, he was afforded a day trip to the 2006 FA Cup final at the Millennium Stadium, when Steven Gerrard famously scored a long-range equaliser in the last minute of normal time before Liverpool went on to win on penalties. "The whole club sort of went down together on the train and it was a great day out," said Flynn. "It was the Gerrard final, wasn't it? West Ham were brilliant that day but he scored two unbelievable goals, and set up the first one."
Flynn might have been unable to reach out and touch the trophy on that occasion, but he is hardly a stranger to lifting silverware in national cup competitions. As part of the Anfield club's all-conquering youth teams - featuring aspiring players such as Adam Hamill, who was once on loan at Dunfermline, and Jay Spearing, who made several appearances for the Liverpool first team - he won back-to-back two-legged FA Youth Cup finals against first Manchester City then Manchester United, scoring in the former then conquering his nerves to score in the decisive penalty shoot-out at Old Trafford in the latter.
"Obviously when you are younger that was everything for you," he said. "There won't be many who have done the double [of FA youth cup and senior] and they will all be Premier League players."
There is a recent history of lower league teams being mercilessly exposed in showpiece occasions at Wembley - think League Two Bradford against Swansea in last season's League Cup final - but there is something about this Sheffield United side that suggests they won't suffer that fate, having come past Premier League sides Aston Villa and Fulham, and teams such as Nottingham Forest who are higher in the league ladder than they are. Part of a six-strong Scottish contingent at the club, Flynn is closing in now on 100 appearances during his time at Bramall Lane and has shown signs of fulfilling his potential under Nigel Clough.
"I would say I am really enjoying my football this season, particularly under the gaffer, although he has been great for all the boys," he said. "A lot of people always say there is a great team spirit at their team, but for us there genuinely is. To have a chance of an FA Cup semi-final, this could be the one and only chance I get in my career."
Not only that, but a place in Europe is also in view for a player who is still Falkirk's only scorer in continental competition, after a goal in a Europa League tie against Vaduz. Meanwhile, of the former Rangers contingent at Hull, only Sone Aluko - whom Flynn recalls playing against when the Nigerian forward was at Aberdeen - is likely to stand in United's way, with Nikica Jelavic cup tied and Allan McGregor injured. "Obviously beating Hull is going to be a real hard ask for us, they are a tough team, but it is a one-off game and you never know," said Flynn.
As for his Wembley experience in 2012, Flynn was withdrawn 10 minutes before penalties began, only to see his side lose 8-7 in the shoot-out after current Rangers goalkeeper Steve Simonsen missed the decisive kick. "I just think it is different," said Flynn. "The playoff final is a real pressure environment, where you are always thinking 'one mistake' or whatever. The FA Cup for us has just been a bonus from where we were, right in a relegation battle. We have worked hard, got ourselves out of it and this is our reward."