Bayern Munich will look to return to winning ways under interim coach Hansi Flick ahead of its Champions League clash with Olympiacos following Niko Kovac’s sacking.

Group B leader Bayern hosts bottom side Olympiacos at the Allianz Arena with a fourth straight Champions League win in its sights after beating the Greek side 3-2 in Athens a fortnight ago.

Bayern already has one foot in the knock-out phase as it currently sits five-points clear of second-placed Tottenham, who it hosts in December having routed the side 7-2 in north London last month.

However, all is not well behind the scenes at the Bavarian giant, which dismissed Kovac on Sunday after winning just three of their last six games in all competitions. The pressure is now on Bayern to perform under caretaker boss Flick against Olympiakos and prove that the weekend’s battering was just a blip.

Flick takes charge of Bayern, albeit temporarily, with ringing endorsements from within the Germany set-up. National head coach Joachim Loew recently said Flick has “enormous qualities”, both for his football knowledge and as a man manager, while team director Oliver Bierhoff described Flick as a “competent expert“.

However, worryingly for both Flick and Bayern, top-scoring striker Robert Lewandowski needs a groin operation, which is likely to take place during next week’s international break and could rule him out for up to 10 days. The 31-year-old is enjoying the best season of his career to date with 20 goals in 16 games, including record 14 in the first 10 Bundesliga matches this season.

Flick confirmed he would play Thomas Muller and Javi Martinez against Olympiacos and used his first training session on Tuesday after the players returned from a day off to work on the defence.

"The goals we have conceded recently have not been Bayern-like. That's what we have to focus on," said Flick.

"We practiced a couple of things we want to see changed and the team did a really good job. I can't change everything – 90 minutes is not enough to change a whole team, but it's about the attitude and maybe changing one or two things tactically, emphasising one or two things differently.

"I want the team to be active and taking the initiative. We need intensity in defence when we are with and without possession.

"Since I've been here I've been fascinated by the talent in the squad. They have enormous potential to perform and we're not seeing enough of that."

The Bundesliga club will hope to coast to a win in Flick's first game in charge and maintain its unbeaten run.

- Spurs vs Red Star Belgrade in battle for third place -

Mauricio Pochettino's Tottenham will engage in a battle for third place when it travels to Serbia to take on Red Star Belgrade.

Spurs is currently second on Group B with four points from three games, while Red Star has three points from as many games.

The Premier League side began its campaign with a 2-2 draw with Olympiacos, which was followed by a 7-2 mauling at the hands of Bayern Munich. The side's most recent Champions League fixture saw it cruise to a 5-0 triumph over Red Star, which will serve as a massive boost going into Wednesday's clash.

Another boost for Spurs is Son Heung-min's availability after his red card for his challenge on Andre Gomes was rescinded. The Football Association rescinded his booking on Tuesday, in what came as a big relief for Pochettino's side.

There was some doubt over whether he would travel with Spurs for the vital Champions League clash against Red Star Belgrade, but he was part of the group that left for Serbia on Tuesday.