Koeman is sure the City side his players will face at the Etihad Stadium on Monday is stronger than it was last season, when Everton drew 1-1 away and emphatically won 4-0 at Goodison Park.
But the Dutchman feels the high defensive line deployed by Guardiola can lead to opportunities, even though he admires how his former Barcelona team-mate sets his side out to play.
"The way he likes to play is the most difficult way," Koeman told reporters. "It's really a pleasure to see his teams playing football.
"The Premier League is strong physically on set-plays and they try to play with a high defence and a lot of offensive players in the team.
"If you play with a high defence there is always space behind, we know that, we remember that.
"When we played City at home we punished them for that but I think with the business they did in the summer City are stronger than last year."
While he is optimistic about the possibility of scoring, Koeman knows it will be tough to keep City out at the other end, as Everton target a fifth consecutive clean sheet to start the season.
He said: "If we get a clean sheet, I don't know if it will be a miracle. Maybe yes.
"We are strong defensively but the key to get a good result is also what we are doing when we have the ball.
"When we played them last season I mentioned that we were really lucky to get one point out of that game. On that day they played fantastic football and I spoke about them being the big favourite to win the league.
"After that they started to struggle. That's football, you never know.
"It's difficult to predict who is the strongest. After what I've seen from different teams in the first week I was impressed by United last Sunday. I'm impressed by City.
"But maybe in two weeks, or two months it can be different. City are very strong though, of course."