FC Barcelona have to put memories of their Clasico defeat at home to Real Madrid behind them and recover quickly from their tired legs when they take on Atletico Madrid in the Camp Nou Stadium on Tuesday night in the first leg of their Champions League quarter-final.

Although the defeat to Real Madrid hurt Barca fans, most would say that Barca's lead in the BBVA Primera Liga means Tuesday's game is the most important of the two, but they must be worried by the image Barca gave at the weekend against their traditional rivals.

Key players such as Neymar, Messi and Luis Suarez all looked tired after the international break, while midfielders Sergio Busquets and Andres Iniesta were also off the pace as was Arda Turan when he replaced Ivan Rakitic.

Neymar, Messi and Suarez will all start again, with the doubt that the three days between games has given them the time to recover, but elsewhere Luis Enrique's options are limited.

The knee injury suffered by Jeremy Mathieu means Gerard Pique and Javier Mascherano only have Thomas Vermaelan as a possible replacement and the Belgian is not up to facing top level rivals these days.

One area where the Barca coach could think about making a change is at right back with Aleix Vidal stepping in to replace Dani Alves, who was at fault for Madrid's winning goal, while the adaptable Sergi Roberto could see his energy used to good effect in midfield.

Atletico come into the game in apparently better shape than Barca after kicking off their weekend match early on Saturday afternoon and enjoying a comfortable 5-1 win at home to Betis.

The result allowed coach Diego Simeone, who has seen his side lose twice to Barca this season, to rest key players in the second half and Atletico should be in better physical shape for what promises to be a demanding tie.

The main problem for Atletico is the probable absence of central defenders Diego Godin, Jose Gimenez and Stefan Savic through injury, meaning that youngsters Lucan and Nacho will face Barca, unless Saul drops back to carry out defensive duties.

Lucas and Nacho had few problems against Betis, but Messi, Suarez and Neymar are a different prospect, providing of course they are fit themselves.