Legia Warsaw vs. Borussia Dortmund (Stadion Wojska Polskiego, 20:45 CEST)

Borussia Dortmund face Polish champions Legia Warsaw on Wednesday night, looking to put Saturday's shock defeat to RB Leipzig behind them.

Dortmund are back in the Champions League after a one-year absence from the competition and an excited Thomas Tuchel told reporters that the build-up to the Europe's top competition is like "Christmas and birthday rolled into one."

Nevertheless, the Dortmund manager is expecting a tough game in the Polish capital, despite Legia's poor start to the Polish league season in which they have taken only nine points from eight games.

"We're not focusing on their league performances," he said. "The fact they have some problems in their domestic league will not affect them badly in my opinion. Maybe the opposite.

"The UEFA Champions League is different competition from the domestic league. We expect a tough and even match. We're certain that we'll need a top performance tomorrow."

In his first season as manager, Tuchel managed Dortmund to the quarter-finals of the Europa League where they lost to Liverpool 5-4 on aggregate.

"I coached BVB in the Europa League last season and some games were like Champions League games," he said. "It will be a pleasure to guide the team in the Champions League for the first time, though. The wait for your first Champions League game is like the anticipation before Christmas or a birthday."

The spotlight will inevitably fall on Dortmund's Polish right-back Łukasz Piszczek who is returning to his home country. The 31-year-old faced Legia four times during his spell at Zagłębie Lubin, including a 2-1 final day victory over Legia to clinch the 2006-07 Ekstraklasa, and can expect a hostile welcome from the home fans.

"I have already played friendlies with BVB in Poland so it is not totally new for me," he told press on Tuesday evening. "It does not matter how I will be welcomed by Legia fans. I came to play football here and that is it."

Apart from long-term absentees Marco Reus (adductors), Neven Subotić (ribs) and Erik Durm (knee), Thomas Tuchel has no additional injury concerns.

Legia manager Besnik Hasi will have to make do without injured captain Michał Pazdan and winger Michał Kucharczyk as the club make their first Champions League appearance since 1995.

Bayer Leverkusen vs. CSKA Moscow (BayArena, 20:45 CEST)

Finnish striker Joel Pohjanpalo is the man of the moment in Leverkusen after his hat-trick on Saturday to beat Hamburg in the Bundesliga.

The 22-year-old, who celebrated his birthday on Tuesday, could make his Champions League debut when CSKA Moscow come to town on Wednesday.

"Joel Pohjanpalo has been superb lately and showed on Saturday how strong he is in the 18-yard-box," Leverkusen coach Roger Schmidt told reporters. "Whether he'll start tomorrow remains to be seen, but he's definitely in contention."

Failure to win five of six group phase matches last season gave Leverkusen little hope of reaching the last 16 stage, the round they had dropped out in the previous two years. "We have to reach the Last 16. This must be our objective and our mission," said goalkeeper Bernd Leno, who signed a new contract at the weekend that will keep him at the club until 2020.

After two mentally-tough games to kickoff the Bundesliga season, Leverkusen is boosted by Kevin Volland's quick recovery from a broken arm. The multiskilled forward broke the club's record transfer fee in the summer, but he has yet to make a competitive start for the club.

Stefan Kiessling came through a late training session unscathed, while Aleksandar Dragovic is still to make his Leverkusen debut and Charles Aranguiz returned after missing out against Hamburg. Karim Bellarabi, meanwhile, will be out for the remainder of the year and underwent surgery on his groin.

CSKA Moscow, second in the Russian Premier League, are coached by Leonid Slutsky, who led the Russian national team to the European Championship this summer. Slutsky's side are kings of efficiency in the domestic setup, conceding just one goal in six games this season.

But the Russians have weapons in attack through Alan Dzagoev and former Everton striker Lacina Traore. "Moscow is ultra-disciplined and tough to play against. If you get the better of the likes of Zenit in the league, you must be a good team," noted Schmidt.

Manchester City vs Borussia Mönchengladbach (Etihad Stadium, 20:45 CEST)

One of the headline clashes of this opening matchday in the Champions League group stage is Gladbach's trip to the Etihad Stadium, which was re-arranged for Wednesday after torrential rain in Manchester saw the game postponed on Tuesday.

Pep Guardiola's Manchester City are one of the in-form teams in Europe, boasting a 100-percent record in all competitions, which includes their impressive 2-1 win at Old Trafford in Saturday's Manchester derby.

Despite his side's impressive start to the season, coach Guardiola has sought to temper expectations of a strong run in the Champions League by claiming history is against his new club.

"I have to be honest, I would have to be a really good coach to win the Champions League this season," Guardiola said. "I will try but the history is the history. If they believed I failed in Munich because I didn't win the Champions League I have to accept that but I never said it is how I would be judged."

Andre Schubert's Gladbach, by contrast, have had a mixed start to the season. An emphatic 9-2 aggregate win over Young Boys in their Champions League qualifying playoff was followed by an impressive 2-1 opening day Bundesliga win over Bayer Leverkusen. But a second half collapse at Freiburg on Saturday led to a morale-sapping 3-1 defeat - not the ideal preparation for a Champions League group that includes Barcelona, Celtic and of course City.

"We know that we need to give our all against a team with real quality," Schubert said ahead of his side's Monday-evening training session in Manchester. "Man. City's start to the season speaks for itself. I understand Guardiola might be trying to lower expectations but they have incredible strength and a great chance to win one or two trophies."

Gladbach will be without Patrick Hermann, who picked up a hamstring injury in the defeat at Freiburg, while Manchester City could welcome Ilkay Gundogan into their squad for the first time since joining from Borussia Dortmund in the summer. The midfielder has been recovering from a dislocated knee suffered in May. Sergio Aguero should return to the City starting lineup, despite being one game into a three-match domestic suspension.