European giants Liverpool and AC Milan, who fought out an epic Champions League final last year, face a tense day as they attempt to reach the group stages of this season's competition.
Liverpool travel to the neutral venue of Kiev with a slender 2-1 lead over Maccabi Haifa while Milan have a 1-0 lead ahead of their trip to Red Star Belgrade in final qualifying round, second leg ties.
Adding to their problems are major injury worries.
Liverpool are without Jamie Carragher and John Arne Risse while Milan, who are in the tournament despite being implicated in Italy's match-fixing scandal, have been hit with captain Paolo Maldini, Alessandro Nesta, Kakha Kaladze and new signing Daniele Bonera all carrying knocks.
Rafael Benitez, the Liverpool coach, believes his team will shake off their early season sluggishness and take their place in the lucrative group stages.
In the first leg at Anfield two weeks ago, Liverpool needed a late goal from Mark Gonzalez to ensure a slight advantage to take to the Ukraine where the match has been moved due to the security situation in the Middle East.
"We are further down the road to full fitness and will be better for it," Benitez said.
"Haifa did very well at Anfield, but they were able to sit back and try to frustrate us. They will not be able to do that so much in this second game," he said. "They will come forward more and we have the players who can take advantage of that."
There's plenty at stake in today's games.
By making the group stages, each club is guaranteed around 18 million euros (US$23 million), cash that is vital for the continent's big guns to maintain their spending power.
Milan's defensive injury crisis shows no sign of easing.
They are likely to line up at the back with Brazilian Marco Cafu playing on the right, Giuseppe Favalli partnering 40-year-old veteran Alessandro Costacurta in the center, and Serginho on the left.
Cafu, a World Cup winner with Brazil in 2002, said the match against Red Star will shape the season of the six-time European champions.
"It's an incredibly important match for us and will define the campaign," he said.
"We respect Red Star, but we have to be aggressive if we are to go through," Cafu said. "They played really well at the San Siro. They are a young squad and play good football."
Red Star, European Cup winners in 1990-1991, beat Irish side Cork City in the second round.