The Bayern Munich coach spent four silverware-laden years in charge at Camp Nou and created arguably the finest club side of all time in the process.
The 19-year-old, who is currently on a season long loan at Everton, believes the standard of football Guardiola produced during his tenure at the club is impossible to repeat.
"Barcelona will never play like they did under Pep Guardiola ever again," he said, in an interview with Four. "Tata Martino is doing a good job but it will never be the same as it was under Pep."
The Catalan prospect then revealed how much he is enjoying his experience of playing Premier League football and admitted the atmosphere at games in England is head and shoulders above La Liga.
"I feel fabulous," he continued. "I relish taking to the field in the Premier League. If I were a supporter I would pay good money to watch it.
"The passion of the fans in England is spectacular and, to be honest, Spain cannot compete with it."
Deulofeu has made nine appearances for Everton this season, scoring once.