Lexi Thompson and Meena Lee head a crowded leaderboard after the opening round of the Wegmans LPGA Championship in New York.
Thompson and Lee carded six-under par rounds of 66 at Monroe Golf Club in Pittsford but the top 15 players are separated by only three strokes.
It looked like being a wide-margin lead for Thompson when she reached seven-under with a birdie at the 14th but, after looking in such good form, she bogeyed 15 and 16 before picking up an eighth birdie of the day at the last.
Lee matched Thompson's round score for score, with eight birdies and two bogeys, although she finished strongly picking up shots at her 16th and 17th holes.
They are one shot clear of America's Brittany Lincicome and Lisa McCloskey of Colombia, who came home with one of the best finishes of the day - she birdied six of her last eight holes after being one-over par through 10.
Lincicome and McCloskey were joined on five-under late in the day by Canada's Jennifer Kirby, who birdied the last after having dropped a stroke at 17.
Cristie Kerr and Shanshan Feng are in a tie for sixth on four-under with Anna Nordqvist and Catriona Matthew the best of the European hopes after opening three-under 69s.
But it was not such a positive start for Inbee Park, who is looking to return to the top of the world rankings. She only managed a couple of birdies in decent scoring conditions and stands tied for 48th after a level-par 72.