Neymar during a training session, on Tuesday
Berlin: Confident Arsenal travel to Bayern Munich on Wednesday hoping to tame the German champions for a second time in two weeks, and are promising to attack despite a string of injuries.
The English club are on a high after a fifth consecutive Premier League win at the weekend - a 3-0 victory at Swansea - and the timing of their visit to the Bavarian capital could hardly be better.
Bayern dropped their first points in the Bundesliga on Friday with a goalless draw at Eintracht Frankfurt.
It followed 10 consecutive victories from the start of the season and, coupled with their 0-2 loss at the Emirates Stadium on October 20 - their first defeat in all competitions - Bayern have shed some of that invincible aura.
Arsenal's victory over Bayern put Arsene Wenger's side back in contention in Group F with three points. Bayern and Olympiakos have six.
"They (Bayern) will be angry," said Arsenal defender Per Mertesacker.
"We are the first team who really challenged them and beat them. They will be on the ball and try to show that they are back and better than us."
The former Germany international added: "They are clever, the Germans. We showed that we can beat them. That is a good sign, but it will be a different game at their place. "We improved our position in the last game against Munich, but we need to get something out of this game."
Arsenal are missing key players, including Theo Walcott, Alex Oxlade-Chamberlain, Danny Welbeck and Jack Wilshere.
But with Olivier Giroud having scored six goals in his past six games and playmaker Mesut Ozil delivering nine assists in 10 league games, they are not prepared to sit back and defend.
"I would sign today to take a point," said coach Arsene Wenger.
"But to sit off Bayern, with their offensive quality, would be difficult to maintain for 90 minutes. We have to relieve the pressure whenever we can and try to score goals.
"That is our structure of the team, to attack. If you get our players to defend then I do not think we will be so efficient. We have to play every time we can."
Bayern, who last season won all six home games in the competition en route to the semi-finals, are by no means in a slump, and their dominance and string of chances against defensive Eintracht was indicative of the team's attacking instincts.
Chelsea manager Jose Mourinho, on the other hand, will be scrutinised more closely than ever as his ailing side take on Dynamo Kiev in a Group G match.
Despite having won the competition twice, with Porto and Inter Milan, the Portugese is under increasing pressure now that the Premier League champions have been beaten five times in their past seven games.
Mourinho has also rejected suggestions that there was a player revolt against him and dismissed reports that one player would rather lose than play for him as "dishonest".
Chelsea midfielder Cesc Fabregas earlier denied reports that he had fallen out with Mourinho and was behind plans to unseat the manager.
"It's a very sad accusation because you are accusing players, or one player, of dishonesty," Mourinho told reporters on Tuesday.
Group E: AS Roma vs Bayer Leverkusen; Barcelona vs BATE Borisov
Group F: Bayern Munich vs Arsenal; Olympiakos Piraeus vs Dinamo Zagreb
Group G: Chelsea vs Dynamo Kiev ; Maccabi Tel Aviv vs Porto
Group H: Ghent vs Valencia; Olympique Lyon vs Zenit St Petersburg