Guardiola was speaking to the press ahead of Wednesday's game away to Everton where a win would put his side level on points with Liverpool (albiet with an extra game played) and return them to the top of the table on goal difference.
Monday night saw Liverpool disappoint with a 1-1 draw away to West Ham, after which Liverpool boss, Jurgen Klopp said the battle for the title was a three-horse race between his team, Manchester City and Tottenham, but Guardiola thinks there are other teams still in the mix.
"I never said Tottenham were not there, nor Chelsea. I never ruled out all five-six teams, and (Manchester) United is making this run of victories every single week, they'll be there to fight for the Premier League," he said.
Chelsea are currently nine points behind City, while Manchester United have an 11-point deficit to make up, but Guardiola insisted that neither could be ruled out as candidates.
"If Chelsea is able to do (win) games in a row, they'll be contenders too to win the Premier League, so everybody is there. The gap is not too big."
"With 39 points to play for, when you are nine, ten points behind, it's not too much. Seeing what's happening right now in the Premier League, everybody is ready to take points," he insisted.
Consecutive draws for Liverpool have seen Guardiola's side snatch back three points at the top of the table in under a week and he said that showed how quickly things can change in the title race.
"Three, four days ago we were already done... The champion was (going to be) Liverpool and now we are the favorites (to win the title) and maybe in three days we are leading or we are seven points behind."
"There will be a lot of surprises and it will be tough for every team to win all of their games because the contenders and non-contenders and all the teams have the abilities, capacity and skills to create problems," he concluded.
Meanwhile, Everton coach Marco Silva insisted his side would do everything possible to beat City on Wednesday, despite their intense local rivalry with Liverpool.
