Former Barca boss Guardiola returns to the Nou Camp on Wednesday for the first of two big meetings between the clubs in Champions League Group C.
Guardiola is a legend in Barca after winning 14 trophies, including two Champions Leagues and three La Liga titles, in his four-year spell in charge of the Catalans and current boss Enrique is expecting a stiff test.
He said: "We have already said how difficult this game is going to be, not only because of the quality and high class of their players individually, but as a team.
"You can already see, at the beginning of the Premier League, many differences compared to previous seasons. You can already see the hands of Guardiola and I am sure the team will keep improving. They play very attractive football.
"For us it is a great challenge and not only because we are trying to get first place in the group. It is Man City led by Pep. We know it is going to be more difficult than previous seasons."
He added: "I can't imagine a better game for any football fan, not just City or Barca fans, but football fans in general."
Punters looking to use a free bet might fancy backing City to get a positive result in Guardiola's return to the club.