GLENEAGLES, Scotland — The United States limited the damage on the opening day of the Solheim Cup by making 18th-hole birdies in the final two matches of the afternoon four-balls to secure half-points and trail Europe, 4½-3½. Jessica and Nelly Korda played central roles in both sessions Friday, teaming up as the first siblings to play together in the competition and winning, 6-and-4, in the morning foursomes. They were split up by US captain Juli Inkster in the afternoon and placed in the final two matches in the four-balls, a decision that looked like it was backfiring as the Americans went to the 18th hole trailing in both. However, Lexi Thompson — playing alongside Jessica Korda — rolled in a 15-foot birdie from left to right to halve a match against Bronte Law and Carlota Ciganda in which neither side led more than 2. Then, with shadows lengthening on the 18th green, Brittany Altomare (of Shrewsbury, Mass.) — Nelly Korda’s partner — holed a birdie from 25 feet up the slope to complete a US comeback from 4 down with six holes to play against Charley Hull and Azahara Munoz. It could be a big momentum shift for the Americans, who are looking for a third straight win in the biggest team event in women’s golf.