With five teams in the bottom half of the UEFA Champions League draw already assured of a place in the next round, Arsenal and Roma are among the only heavyweight contenders yet to secure their progress.
The Gunners host Partizan Belgrade on Wednesday, knowing that victory against the Group H whipping boys will guarantee their place in the last 16. Arsenal's group is the only pool in which both qualification berths are yet to be decided, but group leaders Shakhtar Donetsk require only a point at home to Portuguese competition debutants Braga to advance.
Victories for Arsenal and Braga, however, would leave three teams tied on 12 points at the top of the group. Should that scenario arise, Arsenal would almost certainly progress due to their superior goal difference in the head-to-head matches between the sides, but Braga would need to beat Shakhtar by four goals to pip the Ukrainians.
Arsenal will again be without Belgian centre-back Thomas Vermaelen (Achilles), who is out until the end of the year, but French midfielder Samir Nasri is in the form of his life after firing the Gunners to the Premier League summit with a delightful brace in Saturday's 2-1 defeat of Fulham.
"I think he is one of our best players of the season and on Saturday he showed it again," said Arsenal full-back Bacary Sagna of his France colleague. "Because of him we won the game. I'm not surprised to see him playing like this. He needed to settle a bit but now he is showing his best and he will show even more."
Arsenal won 3-1 when the sides met in Belgrade in September and Partizan are yet to pick up a point in five group matches.
Last season's beaten finalists Bayern Munich have already booked their place in the Round of 16 and Group E rivals Roma are in pole position to join them after coming from behind to beat the German giants 3-2 in their last outing. Roma have nine points, three more than nearest challengers Basel, and Claudio Ranieri's men will advance if they pick up a point on their trip to Romanians CFR Cluj. Basel must win at Bayern and hope Cluj pull off an upset against Roma, otherwise they will have to make do with a spot in the UEFA Europa League.
With Real Madrid and AC Milan already through in Group G, the only issue to be resolved is whether Ajax or Auxerre secure the consolation prize of qualification to the Europa League. Ajax currently lead the French outfit by a point but both teams face daunting games on Wednesday, with the Dutch club travelling to Milan and Auxerre tackling Jose Mourinho's Real Madrid at the Santiago Bernabeu.
"I don't expect Auxerre to win in Madrid, but you never know, so actually we need to try to get a good result against Milan," said Ajax's Dutch international goalkeeper Maarten Stekelenburg.
All the issues have already been settled in Group F, where group winners Chelsea have sealed a last-16 place alongside Marseille and third-placed Spartak Moscow are six points clear of rock-bottom MSK Zilina. Chelsea's trip to Marseille will mark Didier Drogba's first visit to Stade Velodrome since he left the French club in 2004 and he says he is looking forward to renewing acquaintances.
"It's funny, because I only played one year in Marseille but the feeling between the fans, the city, and me is unbelievable," he told uefa.com. "I gave everything and they gave it back to me as well. They still love me and it's nice when I go there."