Karlsson finished his round with a curling, 20-foot birdie putt at the ninth hole.
"You always need a bit of luck to putt well," said Karlsson. "The way the pins were put today, you are going to miss a few greens. And if you are just a little bit out you are going to catch one of the slopes on the greens and then you will be off. You definitely need to have a bit of luck to hit the right shots at the right time and I had that."
Faldo made another move in his bid to jump into the top 20 of the European Order of Merit and thus secure a place in the World Golf Championships American Express Championship later this month.
"I am just trying to be very disciplined out there, trying to do what I want to do on each shot and if I keep doing that we shall see," Faldo said. "It is good to feel a bit of pressure, because that is how you learn what to do with your golf swing to make it happen, the key things that have to happen to get the good shots when you want them."
Those tied for fifth place at 67 included Alex Cejka, Miguel Angel Jimenez, David Park, Carl Pettersson and Brett Rumford. British Open champion Ernie Els bogeyed the last hole to open with a 70. Among those at 71, tied for 26th place, were Craig Stadler and his son Kevin.
Kevin Stadler is playing in his first professional tournament on a special invitation after reaching the quarterfinals of the U.S. Amateur two weeks ago.