Before the third day in Berlin, Karlsson led by four strokes and there were four Swedes among the top five.
She had the lead, mainly thanks to a fantastic Thursday when she went nine under par.
On Saturday, she had it tougher and therefore the lead is now only one stroke big.
Karlsson went one under par, while Stark was four strokes better.
In total, Karlsson is at -14.
Divided third by ten under par are the Spaniard Carmen Alonso and the home player Leonie Harm.
Karlsson has never won the European Tour before, so Sunday will be a big day for her.
- It was OK.
I had some problems on the greens today.
But other than that, it was good, she says about today's round.