Panathinaikos could be on the receiving end of a Champions League backlash from a wounded Barcelona tomorrow after the La Liga giants were stunned 2-0 at fortress Nou Camp by unfancied Hercules at the weekend.
Barca host the Greek side for their opening Group D clash smarting from a first home defeat in the Spanish league since May 2009, one that defender Daniel Alves said had raised the hackles of coach Pep Guardiola's players.
"Winning is the only thing that matters at this club and when we don't win we get angry," the Brazilian said.
"Whatever team we're facing we're always motivated to win and Tuesday will be no different. We'll go out there with the same motivation but we hope that we show a bit more quality."
Barca were denied a second straight triumph in Europe's elite club competition when they lost out in last season's semi-finals to eventual winner Inter Milan. The Catalans will be keen to lay down a marker and kick their latest European campaign off with a convincing home win.
However, the 2009 winners were worryingly toothless against Hercules, but Spain midfielder Andres Iniesta, scorer of the winning goal against Holland in the World Cup final in July, said the Barca players would learn from the defeat and move on.
"We play a lot of matches and we know that what counts is the day to day," he said. "This was a lesson for us and that's that."
Panathinaikos warmed up for Tuesday's match with a 1-0 win at Aris Salonika.
France international Djibril Cisse, who helped Panathinaikos to a Greek league and cup double last season, scoring 29 goals in all competitions, netted the winner at Aris and will likely play as a lone striker at the Nou Camp.
Midfielder Lazaros Christodoulopoulos, striker Antonis Petropoulos and defenders Giorgos Seitaridis and Nikos Spiropoulos will not travel due to various injuries.