SOTOGRANDE, Spain -- Soren Kjeldsen of Denmark shot a 6-under 65 on Thursday for a three-stroke lead after the first round of the Volvo Masters, and Lee Westwood surged ahead in the chase for the Order of Merit title.
Sergio Garcia finished with a 68 to finish second on a windy day at Valderrama.
Karlsson initially struggled with his putter but rallied for a 73.
"The greens were so quick that if you just missed a few then you could also lose your confidence," Karlsson said.
Three-time major winner Padraig Harrington, Karlsson's closest competitor for the European Tour's money title, was three shots behind him.
Westwood and Harrington could win the Order of Merit with a victory coupled with Karlsson finishing no higher than fourth. Jimenez also needs to win and have his three competitors finish near the bottom to secure the title.
"I don't think you can feel comfortable around this golf course, but I have the patience to go out there and work for my shots," Westwood said. "It's a grind, but I enjoy grinding. I do feel like it suits me more."
Harrington reached only two of the first nine greens in regulations and tough chips at No. 2, 4 and 5 resulted in bogeys as he made the turn at 3-over without a birdie.
"It's been proven before that it's not hard to come back on this golf course," Harrington said. "We have 54 holes of golf to play, the tide will turn at some point."