Eighth Sofia coach of year chases Europa win
Manchester City, Sporting, CSKA Moscow, Zenit St Petersburg, VfB Stuttgart, Porto and Paris Saint-Germain will guarantee a place in the knockout stages if they win.
Milen Radukanov will be in the hot seat when 31-times Bulgarian champions CSKA Sofia seek to restore some fading credibility at Rapid Vienna in Group L.
Radukanov is performing a caretaker role although the terms 'interim' and 'long-term' are almost interchangeable when it comes to describing coaches at the former army club.
CSKA Sofia, twice European Cup semi-finalists during the Communist era in Eastern Europe, began the year with former striker and crowd favourite Luboslav Penev as coach but he resigned in January.
Ioan Andone replaced him, only to quit two months later after picking up two wins in six matches.
"He came here with big ambitions but unfortunately he won't be able to fulfil it," said chief executive Ventsislav Zhivkov.
Andone's assistant Adalbert Zafirov took over on an interim basis until Dimitar Penev, who led Bulgaria to the semi-finals of the 1994 World Cup, stepped up in April.
However, he lasted only one month and by the time Pavel Dotchev took charge in May, Zhivkov was finding it all too tedious.
"It's a bit boring to name a new coach so often (but) I think Dotchev is the right man," said Zhivkov.
Dotchev said: "I will do my best to give our fantastic fans lots to cheer about. CSKA's ambitions as always are to win the domestic double and get as far as we can in European competition."
However, he also quit after two games of the new season, saying: "There were many difficulties and obstacles. I didn't have support in my work but I'm leaving with my head held high."
Then came Sasho Borisov, another interim appointment, followed by Macedonia's Gjore Jovanovski who was fired following a 2-0 home defeat by Rapid Vienna two weeks ago.
Rapid, Austria's most successful club in terms of domestic titles, have three points and could revive their chances in Group L where Porto, leaders with a maximum nine points, host Besiktas who have six.
Manchester City visit Lech Poznan in Group A where former European champions Juventus, who have drawn their first three games, host Austrian champions Salzburg.
Group K leaders Liverpool, unbeaten in Europe this season, host Napoli who have also recorded three draws.
Palermo, beaten 3-0 at home by CSKA Moscow, will not relish their Group F return in Russia.
Sampdoria, who also went down to Metalist Kharkiv, may have a better chance of three points when they host the Ukrainians in Group I.
Holders Atletico Madrid, who notched their first Group B win at home to Rosenborg Trondheim two weeks ago, visit the Norwegians while Paris St Germain entertain Bundesliga leaders Borussia Dortmund in Group J.