The Citizens are amongst the hottest performers in Europe this season and made it 18 successive Premier League wins on Wednesday to sit 15 points clear at the top.
City are also expected to be part of the quarter-finals of the European Cup as they face FC Basel over two legs in the last-16.
But when asked if the Manchester giants were the title favourites, Guardiola said: "Who does [Lionel] Messi play for?” referring to Barcelona.
"So they're the favourites," Guardiola added.
