LANCASTER - Australian veteran Karrie Webb staged a back-nine birdie blitz to grab a share of the first round lead at a storm-hit US Women's Open on Thursday. Seven-time major champion Webb rolled back the years with a near-flawless opening round, starting with 10 straight pars before notching four birdies down the stretch to finish with a four-under-par 66 at Pennsylvania's Lancaster Country Club.

The 40-year-old Queenslander, who won back-to-back Opens in 2000 and 2001, said past experience had taught her to keep her emotions in check as she looked to get off to a smooth start in the tournament. "I still have my challenges at a US Open," Webb said. "You always want to do well at this event. And for me it's about controlling my emotions and not getting too high or too low, especially in the first couple of rounds. I did a really good job of that today. I played very well, I didn't miss a fairway. When you play like that, it's not easy but it's less stressful than I could have made it."

Webb finished her round several hours before klaxons sounded across the course shortly after 6pm local time as an electrical storm churned towards the region. Play was later halted for the day with several players left out on the course. Joining Webb at the top of the leaderboard was 24-year-old Marina Alex, who drained three birdies on her final five holes to also finish on 66.

South Korea's Amy Yang was a shot back with a three-under-par 67. The first round leaderboard could easily look different on Friday however with Choi Nay-Yeon on three under after 15 holes and Jane Park of the United States three under after 13. New Jersey native Alex has endured a rollercoaster season on the LPGA circuit this year, at one stage missing five consecutive cuts before posting her first top 10 finish of the season a fortnight ago.

Alex revealed she was starting to reap benefits from technical tweaks she had implemented in recent months. "Now that I've put some of these changes into play a little more often, I just feel more comfortable and I'm making freer swings and the results are showing from that," Alex said. New Zealand prodigy Lydia Ko remains firmly in the hunt, four shots off the lead after an even par 70, grouped with seven other players including English veteran Laura Davies.

However it was a disappointing start for defending Open champion Michelle Wie, who shot a two-over-par 72 after struggling to get to grips with the demanding 6,353-yard layout, carding four bogeys and two birdies. Wie however was bullish about her chances of being able to challenge over the remaining rounds. "You can't win the tournament on the first day, but you definitely can lose it," she told reporters. "I definitely feel like I'm in there. I think I held it together today. I had a lot of opportunities where I had to make big putts, and I'm proud of myself for that," she added. "It's a tough golf course, so I think you have to try to make birdies when you can."