Everton won the race to sign exciting Barcelona starlet Gerard Deulofeu, with the 19-year-old joining the English Premier League side on a season-long loan.
Deulofeu becomes Everton's fourth signing of the summer, with Martinez already completing deals for Arouna Kone, Antolin Alcaraz and Joel Robles.
"Everton have signed exciting Barcelona starlet Gerard Deulofeu," the club said in a statement on their official website.
"The 19-year-old forward arrives on a season long loan and with a reputation as one of Europe's finest young prospects."
Martinez hopes Deulofeu can make a big impact at Everton and has tipped the forward to become a big star in the future.
"Gerard is a real diamond of Spanish football and a boy with incredible footballing talent and I am delighted that he has chosen to take the next step of his career with Everton," Martinez said.
"He is a young man with a lot of potential to be a real star and the Everton family is the perfect environment for him to progress.
"The warmth, patience and understanding of Goodison Park is exactly what he needs to carry on fulfilling his potential.
"The experience that we have in our dressing room will help him in his development and he will bring a completely different penetrating approach to our group.
"We understand a lot of other top clubs around Europe were interested in Gerard so it is fantastic he has joined us."
Meanwhile, Everton skipper Phil Jagielka welcomed the new signings to Everton, particularly that of Kone and Alcaraz.
"It is nice to have those type of players on our team this time," he said.
"Obviously they are two players that the manager knows very well, two players who were big stars at Wigan.
"I know Kone played most of their games and scored most of their goals and was a really big handful.
"Alcaraz unfortunately had a few injuries last season and didn't play as much football as he would have liked but, the same again, he was a very important player for Wigan.
"They are two fantastic signatures to get and hopefully they can come into what is now a good squad and make it a little bit stronger."