If you meant winning the treble again, then yes it would be unbelievable. City won their first CL title last season and made it even more special by winning the treble, but to do that all over again this season, something that has never been done, then that would be an unprecedented feat. Pep's men already have one foot in the CL QF, and they are still alive in both the EPL and the FA cup, so yes, anything can happen and if it does, it would cement Pep's and his players' legacies in football's history.
Pep Guardiola have always been ready to face his challenges and overcoming them was no difficulty for them. Manchester City going in for another year to win the treble. The question is, can they win or not? Perhapes they successfully accomplished it last season and doing in again wouldn't be a problem. I believed the club are working entirely to improve all weaknesses. Pep Guardiola is becoming more serious this season, a with the looks of things, no one is stopping him from ascertaining greater heights with his club. Manchester City.