Serena Williams has upstaged sister Venus 6-4 6-4 in the Australian Open final to become the most successful women’s player in professional tennis history.Williams overcame a shaky start on Saturday night to land an unprecedented seventh Open title and open-era record 23 grand slam singles crown with an emotional 6-4 6-4 triumph.The all-conquering American not only eclipsed German great Steffi Graf’s modern- day mark of 22 grand slam titles, but also regained the world No.1 ranking she’d relinquished last September to Angelique Kerber.Among countless other records, Williams - at 35 years and 125 days - also extended her own record as the oldest woman to win a major in the half-century open era.Margaret Court fittingly had the best seat in the house, front and centre in the President’s Box at Rod Laver Arena, as Williams also drew within one slam of the legendary Australian’s record 24 singles majors with a typically ruthless display.The superstar siblings were clashing for the ninth time in a grand slam final - but first since 2009 - and this was Serena’s seventh success in the matches that mattered most.After breaking Venus’s serve in the opening game of the match, Serena banished any suspicions she might go easy on her older sister when she obliterated her racquet after being on the wrong end of a net-cord winner from her greatest friend and rival.The second seed received an automatic code violation for the outburst but swiftly took out her frustrations on Venus with a ferocious forehand return winner the very next point.But after breaking Venus again, Serena coughed up three double-faults the next game to immediately give up her advantage.Serena finally held for the first time in the sixth game, broke Venus once more and closed out the opening set with her seventh ace.With a 20-from-20 record in grand slam finals after taking the first set, Serena could see the finish line.But eyeing her own watershed win, 36-year-old Venus stayed with her for much of the second set.Alas, women’s tennis’s fiercest competitor gained her fourth break at 4-3 before closing out the match after one hour and 22 minutes to deny Venus a long-awaited first Open crown - and eighth career major.After losing last year’s final to Kerber, and then the French Open decider to Garbine Muguruza, Serena now holds two of the four grand slam trophies - Wimbledon and the Daphne Akhurst Memorial Cup for her emphatic victory on Saturday night.Source: The New Zealand Herald