Chelsea have made some excellent acquisitions over the summer, and are now many pundits’ favourite to clinch the Premier League title.

The Blues signed Diego Costa, Filipe Luis, Cesc Fabregas, and legend Didier Drogba... as well as having goalkeeper Thibaut Courtois return from loan at Atletico Madrid.

This could be the year that the Premier League trophy returns to Stamford Bridge, but to do so, several players – new and old – need to prove to the fans and the critics they are the champions Jose Mourinho expects them to be.

With that in mind, here are FIVE Chelsea players that need to prove themselves this season.

Diego Costa5

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Diego Costa

Diego Costa 1

Chelsea have had the curse of signing a big name striker, only for them to flop and play nowhere near their massive transfer fees. Over the years there have been Adrian Mutu, Mateja Kezman, Hernan Crespo, Andriy Shevchenko, and who can forget British transfer record Fernando Torres.

Now Diego Costa comes in as the summer’s marquee signing and with 27 goals in La Liga last term looks like a solid purchase, but players before him also had incredible goal-scoring records which they couldn’t replicate at Stamford Bridge.

The Brazilian-born striker needs to score early to ease the pressure on his shoulders, and hopefully become the Chelsea hitman the Blues have lacked ever since Drogba’s previous departure. And with the returned Chelsea legend set to miss the first few months with an injury, Costa has no better chance to prove himself.

Thibaut Courtois

Courtois

Courtois undoubtedly had a fantastic season with Atletico Madrid last term, and now returning from loan seems to be the preferred choice to stand between the Stamford Bridge sticks. But to do so long-serving veteran Petr Cech has been forced to play second-fiddle, despite the Czech international still as solid as ever.

However Courtois' past two seasons itself speaks of his tremendous ability, winning the La Liga Goalkeeper of the Year in 2013 and had the lowest goals to games ratio (Zamora trophy) in both 2013 and 2014.

Mourinho has given Courtois the chance to become Chelsea’s number one for years to come, but he has to prove to the coach and the public he is better than his predecessor.

Cesc Fabregas

Fabregas1

Fabregas moved back to Barcelona from Arsenal back in 2011 and was expected to stay with Catalonia for a long time, but the Spaniard never seemed to settle at the Nou Camp.

Despite a decent goal tally, Fabregas had limited game-time trying to break the midfield trio of Xavi, Iniesta, and Sergio Busquets... which forced him to often play out of position.

Chelsea saw the opportunity and signed the former Arsenal captain this summer, and he is looking to prove himself and win the coveted Premier League, which eluded him during his time with the Gunners.

It would also rub salt into the wounds of Arsenal fans, if he were to win title for their city rivals.

John Terry

John Terry

Everyone knows of Terry’s defensive ability and commitment to the club, but as the Chelsea captain heads towards his twilight years there will be concerns over his pace as well as his fitness.

The 33-year-old will face some stiff competition for the centre-back, with Gary Cahill and Ivanovic both very capable of slotting for the captain. Young Kurt Zouma is also in with a shout, having impressed the manager in pre-season.

Terry undoubtedly has a few seasons left in him, but will any case need to prove to Mourinho he is good enough to help Chelsea win the Premier League title.

Fernando Torres

Fernando Torres

Oh Fernando Torres... this could well be the Spaniard’s last season at the club if he isn’t sold before the transfer window ends this month.

With Didier Drogba now injured for the first few months of the campaign, Mourinho will still need to rely on the former Liverpool star to share the load with first choice striker Diego Costa.

Torres could very well get the nod during Champions League games, and if the Blues need a goal may perhaps come on as a substitute to partner Costa in the Premier League.

Whatever the case, when Torres steps on the pitch, he must prove himself to have any chance of regaining the respect he lost since his £50million arrival back in the January 2011.