Sorenstam, who grew up near the Bro-Balsta course, had five birdies and one eagle, which came on the long par-5 sixth hole. She hit a 4-wood and holed a long, snaking uphill putt.
'It's probably my best round in quite a while,' said Sorenstam, the official host of the tournament. 'I hit all 18 greens, putted well and I was never in a bunker.'
Sherri Steinhauer, who won the Women's British Open last week, was two shots back at 5 under after six birdies and one bogey. Karen Stupples, who played in the same group with Sorenstam and Steinhauer, shared third at 69 with Gwladys Nocera and Helen Alfredsson, the Solheim Cup captain from Sweden.
Laura Davies and Liselotte Neumann were another stroke back, while Lorena Ochoa, ranked second in the world behind Sorenstam, shot a 72 and shared 18th. Charlotta Sorenstam, Annika's sister, had a 75.
Sorenstam is the defending champion, having won the inaugural Ladies European Tour event last year at Barseback in southern Sweden. In the last five years, Sorenstam has won three tournaments in Sweden.
Sorenstam started playing on the Bro-Balsta course when she was 12 with her younger sister. Their parents still live nearby.
'I know the golf course well, and I would like to think it knows I have come home and it's going to give me some good breaks,' she said.
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