Paris Saint-Germain coach Carlo Ancelotti warned his players to get their act together as he prepared for Tuesday's Champions League Group A finale at home to Porto.
Both clubs have already qualified for the last 16 and the game will decide who finishes top of the group with Porto on 13 points from five matches and PSG one point adrift in second spot.
PSG, who spent around 150 million euros on transfers in the close season, suffered their third defeat in five Ligue 1 games when they lost 2-1 at mid-table Nice on Saturday.
The result angered Ancelotti and left his fourth-placed team five points adrift of leaders Olympique Lyon.
"The players have to start taking responsibility," the Italian told reporters. "Everyone has to be serious about this.
"I have got a feeling the players are not all focused on the game plan nor on the club's project," added Ancelotti before warning of "radical solutions" if they do not listen to his pleas.
PSG will again rely on Sweden forward Zlatan Ibrahimovic who has been in inspired form in a new playmaker's role in the Champions League, setting up five of the club's last six goals in the competition.
Porto have also had their problems of late, knocked out 2-1 by Braga in the Portuguese Cup on Friday.
"That was disappointing but we have to move on," said Porto coach Vitor Pereira.
Midfielder Joao Moutinho and striker Jackson Martinez were among several players rested on Friday while playmaker Andre Castro was sent off.
But Porto are confident they can reproduce the Champions League performances that have taken them to the top of the group table.
"We are going to Paris to win and to be first in the group. This club lives off victories," Pereira said.
The Portuguese Premier League leaders, who beat PSG 1-0 at home in October, will again rely on Moutinho to orchestrate their strategy of possession football.
Paris Saint-Germain: 16-Salvatore Sirigu; 26-Christophe Jallet, 13-Alex, 2-Thiago Silva, 22-Sylvain Armand; 20-Clement Chantome, 14-Blaise Matuidi, 17-Maxwell; 11-Ezequiel Lavezzi, 18-Zlatan Ibrahimovic, 7-Jeremy Menez
Porto: 1-Helton; 2-Danilo, 23-Abdoulaye Ba, 30-Nicolas Otamendi, 22-Eliaquim Mangala; 8-Joao Moutinho, 35-Steven Defour, 3-Lucho Gonzalez, 10-James Rodriguez, 17-Silvestre Varela; 9-Jackson Martinez.comments