1948
Margaret Osborne duPont def. Louise Brough 4-6, 6-4, 15-13
Brough (at left) was in her prime, having won the Open the year before and starting a run of three straight Wimbledon crowns earlier in the summer.
She would ultimately claim 35 Grand Slam titles between singles, doubles and mixed doubles. 
du Pont (at right) had notched the French title in 1946 and Wimbledon in 1947. They were undeniably the two best players in the world when they clashed, but also close friends and double partners.
In the finals of 1948, Osborne took the first set and lost the second then avoided a match point in the third, to take the 15-13 marathon third set, the longest in final history. It was the first of three straight US Open titles for Osborne.
The next year Brough got a measure of revenge with one of the most bizarre Wimbledon finals ever, beating duPont 10-8, 1-6, 10-8.
The pair went into the Hall of Fame together in 1967.