Haaland struck twice to take his Premier League tally for the season to 13 goals, seven clear at the top of the Golden Boot race. The Norwegian is now just two league goals away from reaching 100 for City, having scored 98 times in 107 appearances since joining the club in 2022.
Guardiola said Haaland's consistency and influence reminded him of working with Messi during his time at Barcelona, and of the impact Ronaldo had at his peak.
"We played really well again, and Erling was decisive," Guardiola said. "It's a little like when you played with Messi or Cristiano, the influence is so big. Has he reached that level? You look at the numbers, oh my God, yes. He's at the level of Cristiano and Messi in terms of goals.
"The difference is that those two did it for 15 years. You still see Messi scoring in America and Cristiano doing the same in Saudi Arabia. But Erling is at that level now, and without him, things would be tough."
Guardiola praised Haaland's hunger to keep improving and his mentality in front of goal.
"The way he strikes the ball, it's like he's telling himself, 'I'm going to score,'" Guardiola added. "He's incredibly coachable. I'm tough with him sometimes, but he always wants to learn. He's down to earth and lives for goals."
City remain second in the Premier League, six points behind leaders Arsenal, with Liverpool visiting the Etihad next Sunday in what could be a crucial clash in the title race.
"Hopefully Arsenal concede a goal one day," Guardiola joked. "It's only ten games, there are still 28 to go, but I feel the team is getting better and better."
The City boss also expressed frustration with referee Anthony Taylor after Bournemouth's goal, hinting that he has grown used to contentious decisions over his decade in English football.
"I've been here ten years, and we know each other well," Guardiola said. "I just asked him to tell me if it was a foul or not. They are brave here, very brave, especially at the Etihad."
Haaland's latest double not only underlined his dominance in front of goal but also kept City firmly in the hunt for a fifth Premier League title in six seasons.
Mikel Arteta has moved to reassure Arsenal fans over his future at the club, insisting there is no reason for concern despite having only 12 months remaining on his contract.
Barcelona remain in discussions with Manchester City over a potential deal for Rodri, with the Spanish midfielder already having agreed personal terms with the Catalan club.
Jeremy Doku has expressed his delight after signing a new five-year contract extension with Manchester City.
Bayern Munich sporting director Max Eberl has ruled out João Palhinha joining Aston Villa, insisting there is "no chance of an agreement" between the clubs.
