As Paris Saint-Germain joust with Arsenal for top spot in their group, Napoli, Benfica and Besiktas will battle it out Tuesday for last 16 Champions League slots.
Portugal's Benfica, European champions back in 1961 and 1962 in their halcyon days but who have underachieved since, should have secured their passage on matchday five but threw away a three-goal lead at Besiktas.
That Turkish comeback, rekindling memories of Liverpool's historic 2005 Istanbul triumph, has left the group outcome on a knife-edge with Besiktas knowing that a win at eliminated Dynamo Kiev will send them through.
In contrast, the final round of games pits Benfica against a Napoli side who beat them 4-2 back on matchday two in Italy -- while Besiktas were dropping home points against Kiev.
The Turkish side's subsequent win in Italy threw the group wide open and the 14-time national champions' refusal to surrender against Benfica means they now fancy their chances.
Besiktas will hope that their best previous showing -- a 1987 European Cup quarter-final appearance -- will not prove a poor omen. Back then, they lost 7-0 on aggregate -- to Kiev.
Turkish daily Sabah expressed concern Sunday about the weather in Kiev predicting that sub-zero temperatures and snow could spell "danger". The paper added Aras Ozbiliz, Anderson Talisca and Caner Erkin are on the treatment table and set to miss out.
All at stake in Lisbon
The winner of Benfica-Napoli in Lisbon will qualify as group winners, while a draw would be enough to send the latter through given their head-to-head edge. If Besiktas lose, both will progress regardless.
Whereas Benfica warmed up for the game by losing their unbeaten record in Portugal in slumping to unheralded Maritimo at the weekend, Napoli broke back into the top four in Serie A when Slovakia midfielder Marek Hamsik moved to within 11 goals of Diego Maradona's record haul of 115 goals for the club after scoring in Friday's 3-0 romp over Inter Milan.
"As far as we're concerned, we have to go there looking for the win," said Napoli coach Maurizio Sarri.
"It will be a difficult game, but it could be two games in one. For the first 70 minutes it could all be normal, then go one way or the other in the final 20 minutes."
Beyond the tightest group of the season, the final round of games is all about securing pole position and a theoretically softer second round draw.
It's been tight at the top throughout in Group A where there is nothing to choose between Arsenal and PSG, both through and level on points ahead of final games at Basel and home to Ludogorets, both winless makeweights.
Barcelona have already won Group C at the expense of Manchester City who nonetheless accompany the Catalan club through regardless of what happens as City host Celtic and Barca welcome Borussia Moenchengladbach.
Atletico Madrid won Group D by a distance and are the only club in the competition with a perfect record as they prepare to do the double over runners-up Bayern Munich.
Rostov will look to avoid defeat at PSV Eindhoven and see their adventures carry on albeit in the Europa League.
A minute's silence will be held before all matches as a mark of respect for Brazilian side Chapecoense, whose squad was decimated by last week's aircrash.