NEW YORK, Sept 12 (Reuters) - Experience triumphed over youth as Australian Sam Stosur and Zhang Shuai of China beat Americans Coco Gauff and Caty McNally 6-3 3-6 6-3 in a tightly fought U.S. Open women"s doubles final on Sunday. The duo, who also won together at the Australian Open in 2019, produced a near-flawless first set with just two unforced errors, compared to 10 from Gauff and McNally, who were competing in their first-ever Grand Slam final. The teenagers kept their cool in the second set and Gauff set up a break point opportunity in the eighth game with a superb forehand winner to cap a 10-shot rally that drew cheers from the New York crowd, before converting and holding their next service game to close out the set. But Stosur, who won her first Grand Slam doubles title at Flushing Meadows 16 years ago, and Zhang recovered in the third, fending off both break points and dropping only three first-serve points to close out the match. "It was just such a tight tussle the whole match, a few points here and there. We stuck together as a team, played aggressive, went for it as we always do, and it pays off," said Stosur. The 37-year-old, who also won the U.S. Open singles title a decade ago, offered enormous credit to their opponents, after an emotional Gauff - two decades her junior - confessed that the first autograph she collected was from the Australian. "We were playing again a couple of youngsters who even though, they"re so young, but they"ve got quite a bit of experience," said Stosur. "They just play fearless. Credit to them. I think they"re a really great team. Again, no doubt they"re going to be back in situations like this, challenging for titles. Not just yet, not today." It was a rare instance of experience triumphing over youth at this year"s U.S. Open, where 18-year-old Emma Raducanu became the first qualifier to win a Grand Slam title after beating 19-year-old Canadian Leylah Fernandez in the women"s singles final on Saturday.