The England international, who also netted against Wigan on Boxing Day, managed to guide Kevin Mirallas' corner into the net at the start of the second half - despite being wrestled to the floor by the overzealous Lee Barnard.
"I just sort of stood there," Jagielka told evertonfc.com. "I think the guy wanted a piggy back - he jumped on me but I managed to deflect the ball home. I'm not too sure people knew who it was because I was laid at the bottom of a pile.
"It was a great ball in by Kev and I think he put one in for Ossie about five minutes later which he nearly got on the end of.
"It was a game of fine margins and hopefully next time we can come out on top."