Pressel had eight birdies in her bogey-free morning round at Aviara to match Lee at 10-under 134. The American won the last of her two LPGA Tour titles in 2008.
''It was kind of stress-free golf out there today. It was nice,'' Pressel said. ''I had a lot of opportunities, and still, even with eight birdies, opportunities that I left out there, I missed or lipped out. But I just played really, really solidly. I'm happy with the result.''
Top-ranked Lydia Ko was tied for ninth at 7 under after a 70, her 26th straight LPGA Tour round under par - three short of Annika Sorenstam's record set in 2004 - and 29th worldwide.
''I didn't know that the record was 29 until I saw it on Twitter,'' Ko said. ''But to have a record that's already set by a legendary player like Annika, it's pretty awesome that I'm like only three rounds away. But like I said, I'm going to try and take one round at a time. This is a tough course.''
The 17-year-old New Zealander has two worldwide victories this year, winning the tour's Women's Australian Open and the Ladies European Tour's New Zealand Women's Open in consecutive weeks. She has 10 straight top-10 finishes on the LPGA Tour.
Pressel matched the course record set last year by Dori Carter.
''I've been fighting the cut for a little while, so it's nice to be in a different position heading into tomorrow,'' Pressel said. ''I feel comfortable with the way that I'm hitting it. I've got to keep working on the things that I've been doing. I was really good at staying patient, even though I was playing well, not getting too far ahead of myself.''
Lee, the first-round leader after a 65, had six birdies and three bogeys in a 69. The 24-year-old South Korean player won LPGA Tour events last year in Michigan and China.
Alison Lee and Cristie Kerr were 9 under. Alison Lee had a 66, and Kerr shot 68.
The 20-year-old Alison Lee is making her fourth LPGA Tour start as a professional. She won the Pac-12 title last year as a freshman at UCLA and was co-medalist at Q-school.
''I was striking the ball really well,'' Alison Lee said. ''I did miss a couple putts here and there, like on the last hole, I missed like a 4-footer, but overall I played really solid.''
The 37-year-old Kerr won the last of her 16 LPGA Tour titles in 2013.
''It's just a matter of putting four solid rounds together,'' Kerr said. ''I've managed to do two of those so far. ... Just have to be consistent with my rounds the next couple days, and I'll have a shot.''
Fourth-ranked Hyo Joo Kim birdied her final hole for a 68 to join Brittany Lang (68), Maria Hernandez (66) and Yokomine Sakura (67) at 8 under. The 19-year-old Kim, from South Korea, won the Founders Cup on Sunday in Phoenix for her second LPGA Tour victory in 13 career starts.
''The ball-striking wasn't exactly where I wanted it, so to shoot 3 under on this golf course is pretty good,'' Lewis said. ''It was nice getting out early, getting the better greens.''
Defending champion Anna Nordqvist had a 69 to reach 3 under.
Yani Tseng, a stroke back after an opening 66, had a 76 to drop into a tie for 46th at 2 under. She won the 2012 event at nearby La Costa for the last of her 15 LPGA Tour titles.
Michelle Wie was 1 under after a 74. She has an endorsement deal with title sponsor Kia.