As tennis role models go, Rafael Nadal is a good place to start. After losing at the 2015 Australian Open, the great Spaniard turned philosopher when asked ‘if’ winning the third set might have turned the match in his favour.‘“If” doesn’t exist in sport,’ he said. ‘That’s the real thing. If, if, if – never comes. The thing is, you have to do it.’Sabalenka ruled out similar speculation when, after beating Taylor Townsend 6-4, 6-3 to book her spot in the US Open quarter-finals, she was asked about whether she was aware of the threat to her status at world No1.‘I completely separate myself from that, it’s just, “if if if”,’ she said. ‘I’m completely focusing on myself. These scenarios, there’s always scenarios for something, different statistics. So I’m completely trying to stay away from it.’If telling the truth, she’s a woman alone. The stage has been set for weeks, with everything building to New York. If Sabalenka defends her title, and her closest rival Elena Rybakina doesn’t reach the semi-finals, her 99-week run at world No1 will continue. If she doesn’t, it could be Rybakina, Jessica Pegula or Coco Gauff who snatch it from her.For now, Sabalenka remains in the hunt, the first woman to reach six straight US Open quarter-finals since Serena Williams. But if the level she produced against the world No96 is anywhere close to the one she brings to court to face her opponent, Wimbledon champion Linda Noskova, her journey will end there. Aryna Sabalenka is into the quarter-finals at Flushing Meadows for a sixth year in a rowSabalenka has never played Townsend, a left-handed doubles specialist who has been as high as world No46 but can often be found lingering just inside or out of the top 100 in the singles game. But at Flushing Meadows, Townsend can be a silent assassin. Last year, she reached the fourth round, defeating French Open champion Mirra Andreeva en route. Since 2023, she has consistently seen success in Queens, despite going winless at each of the other Slams.Plus, she’s a home favourite, playing on Arthur Ashe Stadium, on the Sunday of Labor Day weekend. Sabalenka anticipated that the crowd would be against her, and they were.As the players walked onto court, it wasn’t immediately clear who was the defending champion, with Townsend swathed in a scene-stealing feathery, floor-length cape, as if taking a cue from best friend Naomi Osaka. But the sequins on the American’s bedazzled match kit could not outdo the $400,000-worth of twinkling jewellery Sabalenka has sported on court this week.Things didn’t get clearer when the match started. What followed was a helter-skelter run of games where neither Townsend nor Sabalenka was able to hold their serve. Breaks were passed back and forth between one another five times before the Belarusian was finally able to win a game off her own racquet, which she chased with another quick-fire break. Taylor Townsend stole the show before the match with an eye-catching outfit But those who might have thought the four-time Grand Slam champion had settled, with the set wrapped up quickly from 5-2 were mistaken.Now, Townsend broke her to love, and things began to get worryingly familiar for the Sabalenka camp. Winning positions have been no safety cushion for her in recent months, and when Townsend claimed her first hold of the match to make it 5-4, Sabalenka looked visibly tense.But here was an opportunity to turn the page, and Sabalenka took it, pushing back Townsend into uncomfortable baseline hitting instead of allowing her to surge up the court and show off her superior game at the net. The 6-4 final scoreline scarcely scratched the surface of the story of the first set.The second set started with a little more rhythm, but Sabalenka was still flummoxed at points. Two of her last three defeats have come against left-handers, and her wickedly sliced serve twice left Sabalenka open-mouthed after whipping the ball and finding only dead air. While Sabalenka never truly lost the upper hand after her first-set scare, her roars of celebration after making a successful serve suggested she knew her game was faltering. Still, she managed to cling on, as a champion can. The tests only get harder from here.