Khachanov's flamboyance
Little split these two players in an extremely tight quarterfinal, with 31-30 aces edged by Kyrgios, but many of Khachanov's came at crucial moments under pressure.
Kyrgios' flamboyance and shot-making ability was on show, but his inability to convert break points, along with 58 unforced errors, ultimately proved the difference, taking two of nine.
Ruthless Ruud
Earlier, Ruud reached his maiden US Open semifinal and fought to keep his world No.1 hopes alive with a gritty win in New York. The Norwegian showed no signs of pressure in dismissing 13th seed Matteo Berrettini with a statement 6-1, 6-4, 7-6 (7-4) quarterfinal victory at Flushing Meadows.
Ruud was at the top of his game in the opening two sets, taking the first inside half an hour, but Berrettini made a contest of the third though the Norwegian pulled it back in the fourth. Into his first US Open semifinal - and his second at a Grand Slam following a run to the final at Roland Garros this year - Ruud, along with Carlos Alcaraz has a chance of becoming the new world No.1
Garcia supreme
On the women's draw, Caroline Garcia kept her terrific form going with a stylish 6-3, 6-4 victory against 18-year-old Coco Gauff in the quarterfinal.
The 28-year-old has now not lost a set in her past six matches, dating back to her final against Petra Kvitova at the Western & Southern Open, and now finds herself in the first Grand Slam semifinal of her career.
Jabeur too makes it
Tunisian Ons Jabeur also advanced through to her first US Open semifinal after defeating the in-form Ajla Tomljanovic 6-4, 7-6 (7-4).
Jabeur, the world No.5, became the first woman from Africa to make the last four at Flushing Meadows after a powerful display in the quarterfinals accounted for an opponent who has belatedly started to pose problems at Grand Slams.