Serena's win means that she has won the most grand slam singles titles in the Open era, the traditional measure of tennis greatness. She surpasses Steffi Graf's 22 and is one behind the all-time leader Margaret Court. (Martina Navratilova and Chris Evert finished with 18 majors each.) And she reclaims the World #1 ranking from Angelique Kerber, who beat her in last year's Aussie Open final.
And there's no indication Serena Williams will stop winning major titles any time soon. My prediction is at least 25, but I do not think she will be playing in 2019. Venus Williams is starting to make noises about playing the Tokyo Olympics in 2020! For Venus, reaching a major final after being diagnosed with Sjogren's Syndrome in 2011 and waiting more than six years between her last major final (2009 Wimbledon) is simply a jaw-dropping achievement which adds to her legacy.
How the Final Was Won
It was the 28th meeting between the sisters (9th in a major final) and Serena improved to a 17-11 head-to-head lead, as well as a 7-2 lead in major finals. (The only Venus wins in major finals came in the 2008 Wimbledon and 2001 US Open.) As with most of their matches, the quality of play was somewhat erratic. It began with four consecutive breaks of service, until Venus became the first to hold to edge ahead 3-2. Serena followed suit and followed up that hold with a break, which she consolidated to go up 5-3. Venus was able to hold serve to force Serena to serve for the set which he did with the help of two aces, including on set point. In the second set the quality of play went up considerably, as Serena calmed down and as both players made fewer errors and the winners were either even (Venus, 10 all) or slightly ahead (Serena, 11-9). The final mini-drama came in the 10th game of the second set (which overall followed the first set, minus the scratchy beginning) after Serena had broken and consolidated her advantage she was serving for the match but fell behind 15-30. But her serve returned and she hit two consecutive good serves (not aces) to go up 40-30 and won on her first championship point due to a Venus backhand error.