Baines was rested for England's friendly victory over Denmark having already been assured of his place in Roy Hodgson's squad heading to Brazil.
Baines and right-back Seamus Coleman - who is Everton's joint second-highest scorer this season with six goals - are giving Martinez plenty of cause for celebration.
Martinez said: "I think the full-back position is the most demanding in world football - you need to be able to defend in a unit, one v one, and full-backs are probably the players who can dislodge defensive set-ups and become vital in your attacking play. We are blessed with the qualities we have.
"Leighton has been playing really well of late and it was a great opportunity for the England manager to see other options (against Denmark) and we are delighted he was rested and can carry on preparing for the game against Arsenal.
"In the case of Leighton he has been such a consistent performer everyone knows what a player he is developing into and what he can bring.
"When you go into a major tournament experience plays a big part and Leighton is probably in the best moment of his career.
"I think he is in the peak of his career to help the national team and from our point of view to help our club.
"I am excited about the ending of the season with Leighton's form and making sure we are as strong as we can be."
Phil Jagielka is not expected to make the FA Cup quarter-final at Arsenal, but fellow centre-back Antolin Alcaraz is fit after more injury problems.
"It is very unlikely Phil Jagielka will be involved. If the game was tomorrow (Friday) he wouldn't be available," added Martinez.