Gross was named as the new coach 18 minutes after Stuttgart sacked Markus Babbel on Sunday and, with the club under fire for a dismal Bundesliga season, the 55-year-old Swiss has his work cut out.
"On Wednesday I want to win. That is where the focus lies. I want to make an early impression," Gross told reporters late on Sunday, before going for an evening training session with his new players, minutes after taking over.
"I want that we battle for every centimetre in every match. That is what I demand from my team."
Stuttgart, on six points from five matches in Group G, will book a knockout-stage spot with a win over the Romanians, who have eight points. A defeat or draw would send them to the Europa League.
Stuttgart, while doing well in the Champions League, are locked in a Bundesliga relegation battle, lying in 16th place after 15 matches with only two league wins to their credit.
Playmaker Thomas Hitzlsperger was stripped of his captaincy days ago while the team let a precious win against VfL Bochum slip through their fingers on Saturday when the visitors equalised a minute from time.
Fans blocked the team bus before the match and police were called in to disperse an angry crowd of several hundred after the draw with Bochum.
"(On Wednesday) I want the players to bring out their best so that the fans are again satisfied with them," said Gross. "I want courageous players and players who will pay back their fans."
The Romanians are wary of Stuttgart's change of coach, saying it will give the German side's players extra motivation.
"Everything happening there is against us. It will be twice as hard for us to accomplish our goal," team official Mihai Stoica said. "In the first game with a new coach, all the players get more motivated."
Urziceni will be without suspended key central defender Vasile Maftei.
Teams (probable):
VfB Stuttgart: 1-Jens Lehmann; 3-Ricardo Osorio, 6-Georg Niedermeier, 17-Matthieu Delpierre, 15-Arthur Boka; 11-Thomas Hitzlsperger, 35-Christian Traesch, 23-Aleksandr Hleb, 32-Zdravko Kuzmanovic; 18-Cacau, 29-Pavel Pogrebnyak.
Unirea Urziceni: 1-Giedrius Arlauskis; 23-Valeriu Bordeanu, 4-Ersin Mehmedovic, 6-George Galamaz, 19-Pablo Brandan, 22-Bruno Fernandes; 30-Sorin Frunza, 18-Ricardo Vilana, 32-Iulian Apostol, 9-Serban Dacian Varga; 7-Marius Ioan Bilasco.
