Jennifer Johnson fired a career-best seven-under par 65 to take a one-shot first-round lead over teenager Lexi Thompson at the Navistar LPGA Classic. Johnson, who has earned a modest $84,809 in her two-plus seasons as a professional, on Thursday pledged to donate half of her winnings this week to the Wounded Warrior Project, which provides services to injured military veterans. "That's some extra motivation," Johnson said. "Hopefully, I can keep it up and give a bunch of money to those guys." Johnson's round was highlighted by an eagle on the par-four 389-yard 15th hole, where she holed out with a six-iron from about 150 yards. "I was trying to land it on the front and I thought it wasn't going to be enough," Johnson said. "I was yelling at it to get up, and then it just kind of curved right in the hole, and then I was happy." Thompson, 16, hit all 18 greens in regulation. Her 66 included seven birdies, four of them in a five-hole span from the 15th. Becky Morgan of Wales and and Alison Walshe were tied for third on 67 A group of seven players, led by world number one Yani Tseng of Taiwan and including Norwegian star Suzann Pettersen, were tied on 68. Thompson first played this event as a 14-year-old amateur in 2009, when she was tied for the lead after two rounds before finishing 27th. Last year, after she had turned professional, she tied for 16th. "I just love coming to this tournament," Thompson said. "It's one I look forward to every year." "I just focused on one shot and thought about tempo," Thompson said. "If I just do that for the next three days, hopefully it will all go well." Morgan was two-over through five holes but bounced back from the slow start to reach five-under, level with Walshe who notched her best round of the year. Morgan birdied four of the final five holes, including the last three. "I gave myself a good talking to and turned things around," Morgan said. "There were a few choice words in there. Sometimes, I need to give myself a good kick in the bum to turn things around."