Madrid, Nov 5 : FC Barcelona return to Champions League action on Wednesday night when they go to Serbia to play Red Star Belgrade (Crvena Zvezda). Hansi Flick's side travelled after another convincing win at home to Espanyol on Sunday in another game in which their rivals were unable to deal with their high press and in which their offside trap worked to annul two Espanyol "goals" for offside. Barca are in excellent form, with 12 goals in their last three games, including five at home to Bayern Munich and four away to Real Madrid, while fit-again Dani Olmo showing he further adds to their attacking options with two goals on Sunday. Flick will bring Jules Kounde back into his side at right back after resting the French defender on Sunday, while Frenkie de Jong or Ferran Lopez also have options of starting in Belgrade.Barca's defeat to Monaco in their opening group game means they have six points from a possible nine in the Champions League and that means they need a win to move into the top-eight of the 32-team group. Barca are currently 10th in the group and that would put them in a play-off ahead of the round of 16, and also mean they will have more games in an already packed fixture list, reports Xinhua.Atletico Madrid travel to face Paris Saint-Germain under even more pressure, with Diego Simeone's side currently 27th in the standings and even outside of the play-off places.A 3-1 home defeat to Lille and a 4-0 thrashing against Benfica have piled the pressure on Atletico after an indifferent start to the season and although their last four group games look slightly easier, another defeat would surely end their hopes of going directly into the last-16. Atletico returned to winning ways with a 2-0 win at home to Las Palmas on Sunday, but PSG will give a better indication of Atletico's current form.Simeone isn't helped by injuries to defenders Robin Le Normand and Cesar Azpilicueta, with Le Normand vital in giving Atletico stability and helping to play the ball out from defense. /IANS