Marcos Alonso has signed a new five-year contract with Chelsea, the club announced on Wednesday.

Left-back Alonso has been in good form for Maurizio Sarri's side, starting all nine of their games in an unbeaten start to the Premier League season.

The 27-year-old joined the Blues in August 2016 in a reported €23million transfer from Fiorentina and helped the club to the Premier League title in his first year at Stamford Bridge.

The Madrid-born defender's league debut coincided with the start of a 13-game winning sequence that set a club record and put Chelsea on course for their sixth league title.

After signing his new contract, Alonso told the club's official website: "I am so happy to stay here longer and to keep playing for one of the best teams in the world.

"It's been a very good two seasons and I am looking forward to more."

Dead-ball specialist Alonso helped Chelsea to FA Cup glory in 2017-18 and contributed seven league goals during the campaign – one more than he scored in the previous season.

Widely regarded as one of the world's best full-backs, Alonso's progress at Chelsea helped him to earn a full debut for Spain when he featured against Argentina in March.

Club director Marina Granovskaia said: "We are delighted to be extending Marcos' contract.

"In the past two seasons he has developed into an important player for the club, demonstrating his outstanding ability and a fantastic attitude that has helped him become a Premier League champion and Spain international."