The Spanish defender played a significant role as Antonio Conte’s side won the title by seven points during the 2016-17 campaign.
Despite the Blues’ dominance last term, questions have been raised over the champions following an underwhelming transfer window.
Alvaro Morata, Antonio Rudiger and Tiemoue Bakayoko have arrived at Stamford Bridge but Conte was said to be ‘fuming’ after a number of deals fell through.
Chelsea’s title rivals, meanwhile, have enjoyed productive windows with both Manchester clubs spending over £150million and Arsenal breaking their transfer record.
Alonso insists the west London outfit are determined to repeat the title triumph but says they will need to improve to compete with their rivals.
‘Motivation for us is easy,’ Alonso told Chelsea’s official website. The most difficult thing for us is the competition.
‘There are so many top teams, they have strengthened their squads with lots of new players.
‘It’s going to be harder than last year – we are going to have to fight as hard or even harder than last year to compete for the title again.
‘We have had a good pre-season with lots of work and we can’t wait to kick off. I’m really looking forward to it.
‘It’s great to be back at Stamford Bridge and as with last year the supporters will be very important again. We start with a tough game against Burnley and we will need them. Hopefully we can have another good year together.’
Conte has also played down Chelsea’s chances of winning the league, saying before the opening game of the season against Burnley: ‘At the start of the season it’s simple to tell that in this league there are probably six top teams and they should fight for the title.
Chelsea 2017/18 Fixtures
Plymouth Argyle (A) – Tues Aug 15
Tottenham (A) – Sat Aug 20
Everton (H) – Sun Aug 27
Leicester City (A) – Sat Sep 9
Arsenal (H) – Sun Sep 17
Stoke City (A) – Sat Sep 23
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‘I think honestly if you have to give an evaluation on paper, it’s right to not put Chelsea as a favourite.
‘It was the same last season for Chelsea; no one believed we could win the title. This season, in this moment, I agree with these people who think this.’