The Manchester City director has warned his side not to underestimate their opponents in the group stage of the competition and is confident of challenging this season
The Etihad outfit have exited the competition at the group stage for the previous two years but face Bayern Munich, CSKA Moscow and Viktoria Plzen in this year's tournament.
And the former Barcelona official has warned his side not to underestimate their opponents as they all possess quality.
"It is difficult to be happy," he told reporters.
"We are happy to be in the Champions League draw, but happy with the current champions in the group, and also going to some countries we don't know too much about, but they are very strong.
"CSKA are current champions of the Russian league and Viktoria Plzen – we have to be careful. But we have to face up to the group.
"Obviously it won't be easy, but we have to fight hard. The champions are in our group in Bayern Munich and we have to be respectful of the other teams too."
City have been backed to make it out of the first phase of the competition and Begiristain believes that is a show of confidence in Manuel Pellegrini's side.
"I am happy with that. It means we are doing well and have a good team. We have made changes with the team and manager but we are confident we can do something important," he added.
"It is very difficult [to reach the last 16]. You are always thinking that you have to do better than in the previous season and we have to be better than last year to get through this time.
"There is no minimum. We are a big club with big players with a very good manager and we will see how the season goes, but we have to be confident with the squad we have."
The Spaniard is confident that City can compete in both the Premier League and in Europe this term, having strengthened their squad over the summer.
He said: "Yes, we are very very happy. We have a minimum of two players for each position."
Finally, he claimed that the club are well placed for the onset of Financial Fair Play at the end of the season.
Begiristain continued: "When I do something, it is because the people of the club allow me to do it."