The Everton boss did not have a good day at the office.
The Swans went ahead in the 17th minute when Gylfi Sigurdsson scored from the penalty spot but the scores were level when Jack Cork put through his own net.
However, just eight minutes later summer signing Andre Ayew scored what proved to be the winner, lifting Swansea four points clear of the bottom three and leaving Everton in 12th place with 29 points.
Confirming that Jagielka was rested for the match, Martinez said, “Medically it was the right time. We need him fully fit for what’s ahead.”
The Everton boss then went on to explain that he would now be without both Besic and Mirallas for the upcoming Capital One Cup semi-final second leg clash against Manchester City.
The Toffees lead that tie 2-1 heading to the Etihad Stadium and they need as many of their top players as they can to ensure they finish the job against the Blues.
RM confirms Jagielka was rested today. "Medically, it was the right time. We need him fully fit for what's ahead." #EFC— Everton (@Everton) January 24, 2016