Both teams won their pool openers 1-0 two weeks ago, PSV at home to Legia Warsaw and Rapid against Hapoel Tel-Aviv in Israel.
Rutten accepts his side will be expected to win the group, but has warned his players that Rapid will be the trickiest hurdle to overcome.
He was quoted as saying at his pre-match press conference on Wednesday evening: "With players aged between 28 and 33, their defence is especially experienced. Their results show they do not concede many goals.
"They may not be very big names, but they work very well as a team.
"That does not change our way of playing, though.
"We will go out to show our strengths. We must go for the win.
"I have a picture of all the teams in the group, and Rapid are the most dangerous team.
"Against the other two, you can score a little more easily.
"We are the favourites in this group and the favourites should show why they are favourites as soon as possible."
Atiba Hutchinson, Przemyslaw Tyton and Stijn Wuytens miss out due to injuries for PSV.
Teenagers Jetro Willems and Benjamin van Leer were among the 20-man squad which travelled to Romania on Wednesday - the former in line for a first taste of European competition following his summer arrival from Sparta Rotterdam - while left-back Erik Pieters has recovered from illness.
Rapid forward Ovidiu Herea has urged his team not to be overawed by their more illustrious opponents at Bucharest's National Arena.
"PSV are a very good team, but we must not be scared of them," he said.
"We have our chance to qualify. We are professional players and we must return after each meeting. We are playing at a new stadium and we want to have as many fans in the stands as we can and make them happy."
Coach Razvan Lucescu will make late decisions on the fitness of midfielder Filipe Teixeira and forward Daniel Pancu.