Raul Rusescu converted a 34th-minute penalty after he was pulled back by Ryan Bertrand to give the Romanians a 1-0 advantage in the last 16 tie ahead of next week's second leg at Stamford Bridge.
Before then, last season's Champions League winners continue their FA Cup defence with Sunday's quarter-final at Old Trafford, a match Benitez insists his players were not distracted by while struggling in Bucharest.
"It's another competition and atmosphere," Benitez said.
"It will be totally different. It's another challenge for us."
