As Arsenal desperately seek a win against the mighty Bayern Munich and Chelsea face a tough test in Ukraine, AFP Sport runs the rule over the games being played in Champions League Groups E, F, G and H on Tuesday (kick-offs 1845 GMT):

Group E

At Barysaw, Belarus

BATE (BLR) v Barcelona (ESP)

Reigning European champions Barcelona are widely expected to see off BATE but should be wary of opponents who beat Roma 3-2 at home in their last Group E game. BATE secured their 10th consecutive Belarusian title on Friday with a 2-0 win at FC Vitebsk giving them an unassailable 10-point lead from nearest rivals Dinamo Minsk with three games to go. Barcelona, meanwhile, travel fresh from beating Rayo Vallecano 5-2 on Saturday as Neymar scored four goals and Luis Suarez once. Such form from that pair should help Barca cope in the continuing absence of the injured Lionel Messi, who scored twice when the Catalans beat BATE 5-0 in Belarus in 2011. Andres Iniesta (hamstring) and Rafinha (knee) are also on the sidelines for Barca.

At Leverkusen, Germany

Bayer Leverkusen (GER) v Roma (ITA)

When the draw was made these two sides were expected to fight it out for second place behind Barcelona, so their upcoming double confrontation, starting with this clash in Germany, is likely to prove decisive. Leverkusen have happy recent memories of facing Italian opposition in the Champions League, having eliminated Roma's capital rivals Lazio in the play-offs in August. They are in a stronger position, having beaten BATE 4-1 at the BayArena before losing 2-1 in Barcelona while Roma followed up a 1-1 draw with Barca by going down 3-2 in Belarus. Roma could do with getting back Edin Dzeko and Francesco Totti, who have been on the sidelines in recent weeks, although without them they beat Empoli 3-1 in Serie A on Saturday, while Leverkusen are coming off a goalless draw in Hamburg in the Bundesliga.

Group F

At London

Arsenal (ENG) v Bayern Munich (GER)

Defeats against Dinamo Zagreb and Olympiakos in their first two Group F games have left Arsenal in urgent need of a win, but now they face a daunting double confrontation against Bayern, who are surely the best team in Europe on current form. At least Arsenal warmed up by winning 3-0 at Watford on Saturday, their third straight victory in the Premier League. "We just need to move on from the first couple of results, they have happened. We know we are capable of getting results against Bayern Munich and we obviously want to put things right," said Theo Walcott. Bayern have won their first two Group F games, scoring eight goals without reply. Pep Guardiola's side also became the first club in the history of the Bundesliga to win their first nine matches of a season when they edged out Werder Bremen 1-0 on Saturday. They achieved that without Douglas Costa, who was rested at the Weserstadion. Arjen Robben and Franck Ribery have also been on the sidelines while Robert Lewandowski, after 15 goals in his previous six matches, failed to find the net with Thomas Mueller getting the winner. Mueller also scored as Bayern won on their last two visits to the Emirates Stadium in 2013 (3-1) and 2014 (2-0).

At Zagreb

Dinamo Zagreb (CRO) v Olympiakos (GRE)

Arsenal's poor start has opened up the group and given Dinamo Zagreb and Olympiakos hope of progressing to the last 16. Both sides have already beaten the Gunners and lost to Bayern ahead of their clash at the Stadion Maksimir in the Croatian capital. The last time Olympiakos went to Zagreb, they drew 1-1 to seal qualification for the quarter-finals of the Champions League for the first, and so far only, time in their history. Marco Silva's Greek champions are in good form just now, too, with an impressive 4-0 win at home to AEK Athens on Saturday, featuring two late goals by talented midfielder Kostas Fortounis, their seventh win out of seven in their domestic league. Dinamo, meanwhile, beat NK Zagreb 4-1 on Friday and are top of the Croatian league. They have lost just one of their last 48 games altogether -- the 5-0 defeat at Bayern last month.

Group G

At Oporto, Portugal

Porto (POR) v Maccabi Tel Aviv (ISR)

Having drawn at Dynamo Kiev and then beaten Chelsea at home, Porto will feel they have the chance to take control of Group G in their next two games against Maccabi Tel Aviv. The Portuguese side host the Israelis at the Estadio do Dragao as they look to continue their unbeaten record this season -- their last defeat was a 6-1 reverse at Bayern Munich in last season's Champions League quarter-finals in April. Coach Julen Lopetegui is expected to be without Brazilian defender Maicon for the rest of this month with a thigh injury but Ivan Marcano should be fit. Maccabi, who are yet to register a point, warmed up for this game by winning 2-1 at Maccabi Petah Tikva in an important match at the top of the Israeli league on Saturday.

At Kiev

Dynamo Kiev (UKR) v Chelsea (ENG)

Jose Mourinho's erratic Chelsea team go to Ukraine knowing defeat would seriously complicate their chances of progressing from Group G. Chelsea eased some of the pressure on Mourinho by beating Aston Villa 2-0 in the Premier League on Saturday, but go into Tuesday's game on the back of a 2-1 defeat at his former club Porto in their previous group match. "Obviously you don't need to lose and lose and lose, because then psychological issues are coming into the game," said the Portuguese, who is without Branislav Ivanovic due to a hamstring injury for the game at the Olympic Stadium. The Ukrainian champions have taken four points from their first two games but are coming off the back of a 3-0 defeat at home to great rivals Shakhtar Donetsk on Friday, their first defeat since losing to the same opponents in the domestic Super Cup in July.

Group H

At St Petersburg, Russia

Zenit St Petersburg (RUS) v Lyon (FRA)

Zenit are top of Group H with two wins from two and can take a huge step towards qualifying for the last 16 by beating a Lyon side with just one point. The Russian champions come into the game at the Petrovsky Stadium on the back of a 2-2 draw at Kuban Krasnodar that left them 10 points adrift of leaders CSKA Moscow in third place in their domestic league. However, in Hulk and Russian international Artem Dzyuba, who scored at the weekend, they have a potentially lethal attack. Lyon's ambitions this season have been hit by injuries, notably to Nabil Fekir, and they have won just four times in 13 games. Hubert Fournier's side needed a late Rafael goal to draw 1-1 at Monaco in Ligue 1 on Friday.

At Valencia, Spain

Valencia (ESP) v Gent (BEL)

After a slow start to the season, Valencia appear to have found form ahead of their home meeting with Gent at the Mestalla. Nuno Espirito Santo's side won 1-0 at Lyon three weeks ago to bounce back from an opening loss at home to Zenit. And they warmed up for this game with a 3-0 win against Malaga on Saturday that featured a goal from talented Portuguese midfielder Andre Gomes. Gent, who are again without the suspended Brecht Dejaegere, have lost just once this season, at Zenit late last month.