Key Champions League games for Barcelona and Atletico Madrid

Barcelona defender Jules Kounde.[Barcelona]

FC Barcelona and Atletico Madrid are in Champions League action on Tuesday night to vie for the last-16 of the tournament.

Traveling to Hamburg to play Shakhtar Donetsk, Barca will look for three points to reach the knockout stage for the first time in three years.

Despite winning their first leg 2-1, Barcelona will be aware their rivals have an effective and brave passing game.

Barca coach Xavi Hernandez will give minutes to Jule Kounde, Robert Lewandowski and Pedri as they work their way back to full fitness, while players such as Marcos Alonso, Yamine Lamal and Ferran Torres could start after being on the subs' bench away to Real Sociedad in La Liga on Saturday night.

Atletico Madrid lost 2-1 away to Las Palmas in La Liga on Friday.

Diego Simeone's side produced a lackluster display in the Canary Islands and need to improve in the key game at home to Celtic.

Atletico dropped two points in a 2-2 draw in Scotland a fortnight ago and can't afford any more slip-ups in an even Group E, where Feyenoord has six points, Atletico five, Lazio four and Celtic just one.

A win for Atletico would make them favorites to progress to the knockout stage, but a draw or defeat would leave them with a lot of work to do against their two toughest rivals in the group.

Simeone could consider bringing Saul Niguez, Marcos Llorente and Angel Correa into his starting 11, although he is unlikely to change his attacking duo of Antoine Griezmann and Alvaro Morata.

He could also consider either dropping Axel Witsel, who doesn't look comfortable in central defense, or pushing the veteran into a midfield position where the Belgian looks more comfortable.