Former Chelsea defender Petrescu, whose nickname refers to his seriousness and British-style coaching discipline, said he had taken his lead from one of the best clubs in Europe to transform Unirea into Romanian champions.
"When I arrived at the club in 2006 I wasn't happy with the way things looked and I decided to change many players," the 41-year-old Petrescu told uefa.com.
"We've sold 24 guys and bought 22 ... The example we have followed is Manchester United where the manager has the final say on all buying and selling, rather than the board.
His side, who lost 2-0 to Sevilla in their Group G debut, host VfB Stuttgart on Tuesday - at Steaua Bucharest's ground rather than their own small stadium, prompting some inventive selling to try to boost attendance in the country's capital.
The cheapest tickets cost 20 lei ($6.97) and the club has distributed free tickets to sport schools and is even telling spectators to come along just to watch Stuttgart's bigger names including Romania striker Ciprian Marica.
"Come to the stadium," Unirea general manager Mihai Stoica encouraged fans on GSP TV.
"Tickets are cheap and if they don't want to see us at least come for Marica and Co."
The Romanian championship has been dominated for years by wealthier Bucharest clubs and commentators have attributed Unirea's maiden title last season to one man alone - Petrescu.
"(He is) the complete coach," Spanish sports daily El Correo de Andalucia wrote recently. "Petrescu is the one guilty for Unirea's spectacular rise. He decides everything."
Unirea hail from Urziceni, a small town with a population of 17,000 in Romania's southern grain belt, a region suffering with high unemployment and lacking foreign investment.
PREMIER COMPETITION
The club's transfer spending has amounted to around $1 million this season according to soccer portal transfermarkt.co.uk but Unirea will not be intimidated by the richer and bigger clubs in Europe's premier club competition.
"Some Romanian players actually ... they are only waiting for the final whistle to swap shirts with the big stars. Not my team. We'll go everywhere to win," said Petrescu, who was in the Chelsea side who beat Stuttgart to win the 1998 UEFA Cup Winners' Cup although he was sent off late in the match.
The Romanian team head into Tuesday's match on the back of a confidence-boosting 4-1 victory over Astra Ploiesti in the league and Petrescu has some new tricks up his sleeve.
"I'm considering a new playing system to surprise them with something. We have to do more than we did in Sevilla," Petrescu was quoted as saying by daily Cotidianul.
"A draw would be good for us. A victory would be sensational."
