City manager Guardiola is hoping the prolific Norwegian can make the difference for his side as they bid to finally claim Europe's top prize after several years of near misses.
The 22-year-old boasts a stunning record in the competition having netted 23 times in 19 games for previous clubs Salzburg and Borussia Dortmund, while he has also made a brilliant start at City.
Since his £52million summer switch from Dortmund, Haaland has scored 10 goals in six Premier League outings, including two hat-tricks.
Yet Guardiola remains cautious about expecting too much from him as he prepares for the start of City's latest Champions League campaign away at Sevilla.
The Spaniard told reporters at a press conference: "All the players that came in this season, they try to make us better, otherwise (signing them) would make no sense.
"If that is going to help us win the titles, I don't know, but if we rely all on Erling's shoulders we are not going to win the Champions League.
"We have to do well to help him, to create more chances and then he scores goals. Hopefully he can do it.
"He came here because we convinced him - we felt we didn't have many strikers and he could play with us, try to be involved in the way we play. He's settled good.
"I understand completely that everyone talks about Erling but I have three, four, five new players and it's the same for them all, to settle as quickly as possible.
"Hopefully he can help us, of course, but we are not going to just win for Erling. He has a special quality and maybe in the important games he can solve the problems we have, but if we don't play good we aren't going to win games in the Champions League or even the Premier League."
City are without defenders Kyle Walker and John Stones for Tuesday's Group G opener at the Ramon Sanchez Pizjuan Stadium.
Right-back Walker was forced off in the latter stages of Saturday's draw at Aston Villa while Stones has also picked up a knock and was withdrawn after training on Monday.
With Aymeric Laporte also still recovering from knee surgery, deadline-day signing Manuel Akanji could make his debut.
Guardiola said of Stones and Walker: "Both are injured. That's why we are lucky the club gave us Manu Akanji, otherwise we would be in real trouble. That's why the club moved quick to bring in another player in this position.
"We are in a difficult position but it is what it is, mainly because of this incredible schedule of many years. The players are human beings and they cannot sustain this demanding situation for a long time."
Guardiola is hopeful neither are seriously injured but is not yet sure when they will return. Another summer signing, midfielder Kalvin Phillips, could feature in Spain after a spell out with a shoulder injury.