'I am very pleased,' said Sorenstam. 'I needed a good round today and that was it. I am very pleased to have hit a lot of good shots today, I could have had more birdies, but I don't want to be too greedy early on in the year.'
Webb had three birdies and a bogey for her second straight round of 69. The 27-year-old is seeking her fifth consecutive title at this event.
'It's turned out to be the tournament that everybody wanted after Annika had a great round today,' Webb said of the Ladies European Tour event. 'There are a lot of other good names on the leaderboard, so it's shaping up really well.'
Joining Webb and Sorenstam in a tie for third were Becky Morgan (71) of Wales and Australia's Michelle Ellis (70).
Esterl had five birdies on her round to go along with two bogeys to open a two-stroke lead over Italian Silvia Cavalleri.
'It was OK. It was a bit of a roller coaster at times but that's what you have to expect. Tomorrow, I am just going to hang in there and enjoy myself and see what happens again,' said Esterl.