Baines had been linked with a move to Manchester United where he would have teamed up with former manager David Moyes.

But the 29-year-old has now committed to the Merseyside club a day before their derby against Liverpool in the Premier League.

"I can give you good news, Leighton Baines has signed a new contract. It is for the next four years," said Martinez.

"To be able to secure Leighton's best years at Everton means a lot, especially in this January (transfer) window where we are talking about having a strong squad going into the second half of the season."

Baines arrived from Wigan in August 2007 and had 18 months remaining on his contract.

"We are all excited that Leighton will be able to have a long-term future with the club and we are all looking forward to the second half of the season having his experience."

Martinez said the fact they had managed to stave off interest from United and persuade Baines to sign a new deal spoke volumes.

"It represents a strong intent of trying to progress and get stronger and Leighton will bring that on the football pitch," he added.

"He has been performing as one the best left-backs in European football and the best is yet to come.

"To have Leighton with the focus and tranquility to be at Everton for the long term is an incredible boost."