Raheem Sterling struggled for his spot at Manchester City.
The Blues have signed the England international for £47.5m from Man City this summer.
He has never won the Champions League with Guardiola at City whereas Thomas Tuchel managed to win the trophy in his debut season with Chelsea.
But he was a crucial player for Guardiola but seemed to have lost his place in the Man City first-team last season.
‘It was a big surprise [losing his starting role],’ Sterling said. ‘A massive surprise. A change of events all of a sudden.
‘It’s something I had to handle, and that’s why I’m here. The manager, myself, and the people at the club know exactly what the reasons were.
‘I tried to play my football and overcome the situation, but it couldn’t be done. So I had to move on.
‘I haven’t played Champions League football with Chelsea yet. They have obviously won it. I haven’t. They have got bragging rights.
‘But again, I am here to try to win it. I don’t know if I am better off here or there [at Man City] – it is not really my forte.
‘I will just go out and try to help the team as I do every season.’