Chelsea new boy Juan Mata will find himself at his old stomping grounds against Valencia, while Arsenal and Marseille will hope to hold their nerves in order to notch up three crucial points in their Champions League group fixtures. Zenit, on the other hand, will be simply trying to break a Russian jinx against Porto. ESPNSTAR.com takes a closer look at all the clashes happening on Wednesday night.
After just leaving Valencia for Chelsea barely a month ago, Mata will find himself back at his old stomping grounds at the Mestalla, as the Blues look to continue their winning run over the La Liga side, having last triumphed 2-1 in the 2007/2008 group stages of the same competition.
The Spaniard will have fond memories of his former employers, having scored 45 goals in 172 appearances, but will be wary of being overly sentimental as Valencia are in fine form themselves, having won three of their four La Liga fixtures this season thus far.
They will be equally wary of Juan Mata, being aware of his qualities, as well as how well he has adapted to life in London since his move, as the star scored in Chelsea's 2-0 win over Bayer Leverkusen just a fortnight ago.
Bayer themselves have lost their last three fixtures, and will hope to get that winning feeling back against Belgian side Genk. However, it won't be easy for the Germans, as under new Dutch manager Mario Been, Genk have shown an upside in form.
They will always draw strength from their last trip to Germany as the Belgians beat Borussia Dortmund 201 in their 2004 Intertoto Cup third round clash.
Both Arsenal and Marseille will be hoping to reverse their poor starts in their respective domestic seasons by winning in Europe. Of the two, Marseille will be more desperate to stop a slide that has left them bottom of Ligue 1 with three points, and no victories, from six games, which contrasted agaisnt their 1-0 victory over Olympiakos two weeks ago. They will face Borussia Dortmund, who are also languishing eighth on the Bundesliga table after a lacklustre start to their season.
The Gunners on the other hand, will be hoping to grab first spot on the table by beating the Greek Super League champions, and hope that striker Robin van Persie will continue his scoring form after hitting his 100th goal for the club against Bolton last weekend.
Olympiakos will feel confident in their own chances though, as they head to the Emirates on the back of a 100% start domestically, following a 3-2 victory over Ergotelis on Saturday. The Gunners will certainly have to be wary of Belgian playmaker Kevin Mirallas, who many in Greece compare to Cristiano Ronaldo, and if Arsene Wenger's players fail to mark the dangerman out of the game, there could be more furrowed brows at the North London club yet again.
Zenit will be looking at trying make history in Portugal when they welcome Porto. No Russian side have ever managed to beat a Portuguese one in European club competition, which is a remarkable statistic.
The pressure will also be on Zenit in the aftermath of their shock 2-1 loss to APOEL in their last fixture, and Porto will be confident of their chances after having won all four of their last fixtures in Russia.
Zenit will be putting their hopes in Alexander Kerzhakov, who is currently joint-top scorer in the Russian league, and will hope to carry on their winning run after notching a 4-0 win over Tomsk that surged them to the top of their domestic league.
Home advantage could proved a huge factor for Shakhtar when they take on APOEL, as they beat both Roma and Arsenal in European competition last season, and they will be confident of their chances against the Cypriots.
On paper, the fixture between BATE and Barcelona is one of two sides in great form, as the Minsk Voblast side have gone unbeaten at home since April, and boast a record of scoring in all 16 games since.
However, their record against Spanish opposition is dismal, having lost 1-0 to Real Madrid and 2-0 to Villarreal previously. Of course, facing the European Champions will also present a further obstacle to continuing their run, as Pep Guardiola's men have recently curtailed a run of draws by beating Atletico Madrid 5-0 last weekend.
Despite having to contend with a the absence of Alexander Pato, AC Milan should still be relatively untroubled by the visit of Viktoria Plzen, though the Serie A side will be hoping to notch a convincing victory to quieten their naysayers, who have slammed their lacklustre start to Serie A which has left them languishing at 11th spot on the table. However, manager Massimiliano Allegri will have every confidence he can turn things around, especially after their 2-2 draw against Barcelona at the Nou Camp last fortnight.