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 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.
"That was disappointing but we have to move on," said Porto coach Vitor Pereira.
"We are going to Paris to win and to be first in the group. This club lives off victories," Pereira said.
