London:Barcelona's hold on the European title could be loosened with another loss to Russia's Rubin Kazan this week, while five-time winner Liverpool would be closer to Champions League elimination if it loses again to Lyon.
Group qualification for the last 16 knockout stage passes halfway on Tuesday and Wednesday, with Manchester United, Chelsea, FC Porto, Sevilla, Lyon, Arsenal and Olympiakos on the verge of advancing with two games to spare.
But Barcelona, which lost 2-1 at home to Rubin Kazan two weeks ago in one of the biggest surprises in the competition's history, now travels to play the Russian club again in wintry conditions expected to fall to minus 10 Celsius.
After three rounds of games, Group F is the closest of the eight. Barcelona, Dynamo Kiev and Rubin have four points each and Inter Milan _ more than two wins clear in the Italian league _ is last with three.
While Barcelona travels to Rubin, unbeaten Inter also has a long journey to Kiev aiming to end a run of three straight group draws.
The omens aren't good for Barca.
The defending champions go to Rubin after a 1-1 draw with Osasuna in the Spanish league and lost to the Russian side two weeks ago after a 0-0 draw with Valencia. Coach Pep Guardiola's team has won its other seven league games and is top of the Spanish standings but doesn't respond well to draws.
"They are upset, especially at not winning when they were so close. Now we have to go into the cold and win in Russia," Guardiola said after the draw with Osasuna in Pamplona.
"We lost two points right at the end, but that's part of the game. I'm disappointed with the result, but we played very well. We played a pretty complete game, we were in control and I'm happy with that. Now we have to pick ourselves up and prepare for the Champions League game."
Barcelona's position is nowhere near as bad as Liverpool's.
Two defeats in a row in Group E to Fiorentina and Lyon have left Liverpool third in the standings, six behind the French side and three behind the Italian club. Saturday's 3-1 defeat to Fulham was also its fifth in the Premier League.
Liverpool has lost six out of its last seven matches in all competitions but manager Rafa Benitez is convinced his team will turn its season around.
"We have confidence we can do it but we have to take our chances and not make mistakes like today," he said after Saturday's loss to Fulham, where Liverpool also had Philipp Degen and Jamie Carragher sent off. "You have to be calm and keep working hard and find solutions."
Lyon comes off a 1-0 victory at St. Etienne and Fiorentina, which hosts last place Debrecen on Wednesday, beat Catania 3-1 in Sunday's Serie A games.
Victories for Lyon and Fiorentina would put the French team through. That would also mean that Liverpool will have to win its final two games, including a victory over Fiorentina by a three-goal margin, and hope that the Italian club doesn't pick up another point at home to Lyon.
After a thrilling 3-2 victory at Real Madrid, AC Milan is level on points with the Spanish club at the top of Group C ahead of their rematch at San Siro on Tuesday. Winner of a combined 16 European cup titles, they are three points ahead of Marseille and FC Zurich.
Runnerup to Barcelona last season and winner of its third European cup title in 2008, Manchester United has a maximum nine points from three Group B games and has a home match against CSKA Moscow (three points) on Tuesday. Another United triumph at Old Trafford would leave the other three clubs vying for one qualifying spot from the group. Second place German champion Wolfsburg goes to Turkey's Besiktas.
Group D leader Chelsea travels to last place Atletico Madrid on Tuesday on a run of four straight league and cup victories with a 17-0 goals aggregate.
The Blues are strengthened by the return of striker Didier Drogba from a three-game European ban for his outburst against a referee after last season's Champions League semifinal against Barcelona. The Ivorian striker's ninth goal of the season was the fourth of Chelsea's goals in a 4-0 victory at Bolton on Saturday to keep Carlo Ancelotti's team top of the Premier League.
"Having Didier back in the Champions League this week will be great for us," said Frank Lampard, who scored the first of the four goals. "It's a big boost, he's a top-class player in great form. Everyone would want him back and involved.
"Hopefully he can step straight into Europe and continue with his league form because he is scoring in every game now. He's neck and neck with Fernando Torres in the goals chart, but for me Didier is the best in the world because of his all-round game."
If Chelsea wins in Madrid and second place Porto triumphs at APOEL Nicosia, then the group will have been decided with two games to spare. Chelsea has nine points, Porto six and the other two have one each.
Group G leader Sevilla will qualify with a draw at home to third place VfB Stuttgart while Romania's Unirea hopes to move closer to the knockout phase in its debut season by beating Scottish champion Rangers at home.
Arsenal and Olympiakos would both qualify by winning their Group H games on Wednesday. The Gunners, fresh from domestic victories over Liverpool and Tottenham, host Dutch champion AZ Alkmaar and Olympiakos visits last place Standard Liege and victories will put them out of reach.