'The margins are so fine that you can have egg on your face very quickly' - Dundalk boss Vinny Perth aware of Riga pitfalls
For Ireland's top team, the first round of the Champions League qualifiers is a gateway game.
The evidence of recent history suggests that Dundalk's decider with Latvian champions Riga might prove to be the most significant match that they play this year.
Just two Irish sides have scaled this hurdle in the past decade. The Shamrock Rovers team of 2011 and the Dundalk side of 2016 both went on to make the group stages of the Europa League.
Negotiating stage one of the main competition gave them the freedom to advance further and eventually benefit from the parachute option into the second biggest one.
Higher profile days would follow, yet it was an away goals victory against Icelandic side FH that made it all possible. After last Wednesday's scoreless draw in Oriel Park, an away goal is what Dundalk require here to progress.
The rules have changed since Stephen Kenny's side captured the attention of the nation three years ago.
Domestic champions now need to make it through four rounds to get to the Champions League promised land. Back then, it was three. The consolation is that they are guaranteed to drop into the Europa League qualifiers even if they lose their first tie.
What they also have this year is seeded status, which means that they entered this tie with Riga as favourites.
They also know that a tougher test lies in store if they lose and drop into the Europa League qualifiers; Dundalk will face old foes BATE or the Polish champions Piast Gliwice in that scenario.
So it's far from a stretch to suggest that what unfolds at the Skonto Stadium this evening may define the maiden European campaign in charge for Kenny's replacement Vinny Perth, the former assistant turned head coach.
Dundalk's American investors bought the club off the back of the 2016 adventure.
The founder of Peak6, Matt Hulsizer, was present at Oriel Park for the frustrating first leg and some other members of the ownership group have also travelled to Latvia - along with 300 or so away fans that are expected to make most of the noise in a country that is more energised by basketball or ice hockey.
The Americans are taking this investment seriously, and that brings pressure.
Riga are clearly a capable team, and their Russian backers have recruited a mix of nationalities to strengthen their squad, but Dundalk's hierarchy have invested €1m into the first team structures with a view to graduating beyond an opponent of this calibre.
Perth is fully aware of the magnitude of the tie, and hinted that he might call upon some experienced players from the 2016 run who sat out the initial joust.
Doubts around Michael Duffy's availability have presented a headache in midfield where Robbie Benson is pushing for inclusion.
It's in defence where older heads might get the nod with the returning Andy Boyle likely to break up the Seán Hoare and Daniel Cleary partnership and Dane Massey fancied to claim the left-back shirt from Dean Jarvis.
Massey smiled yesterday as he spoke of how his room-mate Daniel Kelly - a winter recruit and European rookie - has been eagerly asking questions about previous trips. The veterans know that the glamour journeys were booked in tense circumstances. Perth's side have practised penalties.
"Top-level sport is always decided by a point or a putt or one moment," mused Perth. "The margins are so fine that you can have egg on your face very quickly. Everybody says we were this amazing football team in 2016 but you go back to that FH game and we won it by the skin of our teeth."
These are sliding doors moments.
That was a night which ultimately paved the way for Stephen Kenny to become Irish manager and for US investors to consider the idea that Ireland has untapped potential.
The serenity of Riga is a world away from the energy at the sharp end of this tournament. But for the protagonists, the stakes are arguably higher.
Dundalk will never forgive themselves if they pass up this tantalising opportunity.
Riga FC v Dundalk, Live on Eir Sport 1, kick-off 5.30