MELBOURNE — Serena Williams knows she must raise another level against “cool cat” Naomi Osaka to keep alive her dream of a record-equalling 24th Grand Slam crown, wary of again falling victim to the Japanese superstar. The pair meet in a blockbuster Australian Open semi-final today with the winner facing either Czech 25th seed Karolina Muchova or American 22nd seed Jennifer Brady in Saturday’s decider. Williams (39) continues to chase Margaret Court’s elusive all-time mark of 24 major titles, after losing four Slam finals since her 2017 victory at Melbourne Park while pregnant. One of those was her controversial 2018 US Open final defeat to Osaka, where the American star was docked a point and a game after losing her temper when warned about coaching. Osaka was booed by some fans and was in tears during the awards ceremony, later calling what should have been her moment of glory “a little bittersweet”. Williams said both players had reached “closure” on the painful moment, which has seen them inextricably linked ever since. “Well, I think we both have had closure, and we have reached out to each other,” said Williams, after overpowering second seed Simona Halep in the quarter-finals. “I have definitely reached out, and she’s — yeah. So off the court, it's hard. I think she’s a great competitor and she’s a cool cat.” They have played each other just once since that New York meeting, in the quarterfinals of the 2019 Canadian Open which Williams won in straight sets. If she can get past third seed Osaka, Williams may never have a better chance to finally seal her 24th title after world number one Ashleigh Barty was upset by Muchova in the last eight on the other side of the draw. Instead, she would face either the Czech or Brady, neither of whom have made a Slam final — in comparison with the 33 played by Williams, who has been in vintage form so far this year. But first up is Osaka, and 10th seed Williams is taking nothing for granted. “Obviously I have an incredible opponent to play, so it would be nice to hopefully keep raising the level of my game. I’m going to have to,” she said. “She’s a very strong player. I feel like she does everything well. She has a good serve, she has a great return, she’s strong on both sides.” Osaka, who swept past Taiwanese veteran Hsieh Su-wei to set up the meeting, is eager to add to her three Grand Slam titles after her wins at Flushing Meadows in 2018 and last year, and Melbourne in 2019. “I always watch Serena’s matches,” she admitted when asked if she planned to do any homework on her opponent. “I grew up watching Serena, Federer, Nadal. It’s just more of a habit than anything. But I feel like everyone in the tournament watches her.” And despite beating Williams in the 2018 US Open final, the 23-year-old admitted to still feeling “really intimidated when I see her on the other side of the court”. “She’s Serena,” she explained. Brady will face Muchova in the other semifinal, with a maiden Slam final guaranteed for one of them. Muchova, fresh from her upset of Barty, said she had note