GLENEAGLES, Scotland — An opening day of swinging fortunes in the Solheim Cup reached a crescendo in a last hour at Gleneagles, with the final two matches of the four-balls going to the 18th hole and the US team staring at a 3-point deficit.
Two long birdie putts later, first from Lexi Thompson then from Brittany Altomare, the US team had escaped with two half-points and trailed Europe, 4½-3½.
The Americans, who lead the overall series, 10-5, are looking for a third straight win in the biggest team event in women’s golf.
As shadows lengthened, it was the US players and their flag-waving fans who were cheering the loudest.
‘‘You keep gnawing a half-point here and a point there, and it adds up,’’ said US captain Juli Inkster, who cut an animated figure beside the 18th green as Day 1 drew to a close.
‘‘You look at all the golf today and we’re only a point down. So I'm very pleased with where we’re at right now.’’
Jessica and Nelly Korda were central in both sessions, teaming up as the first siblings to play together in the competition and winning, 6 and 4, in morning foursomes.
It was the only win for the US team, which went into the four-balls trailing, 2½-1½.
The sisters were split up in the afternoon and placed in the final two matches, a decision that looked to be backfiring as the Americans went to the 18th hole losing in both. Thompson, playing with Jessica Korda, rolled in a 15-foot birdie putt to grab a half-point from Bronte Law and Carlota Ciganda in a match neither side led by more than 2.
Altomare, Nelly Korda’s partner, went even better, holing 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.
‘‘Even though we’re ahead, we’re going to act like we’re behind,’’ said Law, a European rookie whose fist pumps, glares, and animated reactions have already drawn comparisons with Ian Poulter. ‘‘And we’re going to go and get every point we can.’’
Inkster praised the performance of the record six rookies in her team, with Nelly Korda and Altomare digging deep for that crucial half-point after Ally McDonald and Angel Yin delivered a record-tying 7-and-5 win over Swedish pair Anna Nordqvist and Caroline Hedwall in the four-balls.
Europe’s three rookies didn’t do badly, either, with Law picking up two half-points, Celine Boutier earning a 2-and-1 win with Georgia Hall in the foursomes, and Anne van Dam excelling in a 4-and-2 win with veteran Suzann Pettersen in the four-balls.
‘‘Playing alongside the new superstar of Europe was a pleasure today,’’ the 38-year-old Pettersen said of Van Dam, who won four holes for the team on the front nine as she high-fived spectators and cupped her ear after making putts. ‘‘Hopefully some of my calmness rubbed off on her today.’’
The Korda siblings are already revelations after their historic performance, with just four foursomes matches in the 29-year history of the Solheim Cup finishing with a heavier margin of victory.
Jessica Korda — the elder of the sisters by five years — played the senior role after skipping onto the raucous first tee and throwing some moves to the backdrop of ABBA’s ‘‘Dancing Queen.’’
She rolled in a birdie putt at No. 1 to immediately put the US team, 1 up, against Caroline Masson and Jodi Ewart Shadoff, and chipped in for eagle from the fringe at No. 10 to keep the sisters 5 up. In those first 10 holes, the Kordas made four birdies and an eagle, giving them a chance of posting a record foursomes win.
They settled for clinching victory on the 14th hole. They put their arms around each other’s waists and laughed their way down the fairway before celebrating on the green, as their tennis-player parents from the Czech Republic — Petr Korda, who won the Australian Open in 1998, and Regina Rajchrtova, who represented her country at the Olympics in 1988 — watched.
‘‘It doesn’t matter if I hit a bad shot, she’s like, ‘I've got this,’ ’’ Jessica Korda said, ‘‘and it’s the same the other way.’’
In 1998, Swedish sisters Annika and Charlotta Sorenstam made the European team but were never paired in foursomes or four-balls.