Nick Kyrgios' shock admission after staggering feat at Citi Open

Nick Kyrgios has revealed that he "didn't get to sleep until 4.50am" before his semi-final victory at the Citi Open in Washington.

Kyrgios continued his career-best season with another incredible display in the US capital on Friday night (Saturday AEST), as he powered past Sweden's Mikael Ymer in straight sets.

WOW: Kyrgios twist emerges after shock Djokovic announcement

CLASSY: Nick Kyrgios' brilliant act for fan after nasty incident

'TOUGH TO WATCH': Venus Williams' brutal fate in tennis return

The Aussie admitted that he was physically and mentally drained from the previous day, when he finished off Reilly Opelka, before saving five match points in an epic quarter-final win over Frances Tiafoe.

In fact, Kyrgios says he had "so much adrenaline" running through him that he struggled to get to sleep in the lead-up to the last-four showdown.

Fortunately, the 27-year-old had his impressive serve to thank as he beat Ymer 7-6 (7-4) 6-3 in what was the Wimbledon runner-up's fifth semi-final appearance from his past six events.

Only an abdominal strain in Mallorca tarnished the impressive streak.

Quite remarkably for Kyrgios in Washington, the Aussie is still yet to be broken once in the tournament.

Against Ymer, the Aussie did not even face one single break point, in yet another clinical serving display.

Kyrgios brought up set point in the opener with his 80th ace of the tournament and sealed the set with a lovely serve-volley play and backhand flick overhead winner.

The second set also proved a serving duel but the Swede was always going to come out second best against Kyrgios in this type of mood as the Australian reeled off the last three games to prevail in one hour, 34 minutes.

Kyrgios hadn't made a final for three years but now he's reached two in less than a month, including his breakout run to his maiden grand slam title match at Wimbledon.

Nick Kyrgios relieved after booking spot in final

That four-set defeat to Djokovic at the All England Club remains the 27-year-old's only loss in his past 11 matches since mid-June.

"I'm just happy to be in another final," Kyrgios said.

"I didn't get to sleep until 4.50am. I had so much adrenaline. I ate some dinner, got some treatment and just my body was so sore after last night.

"It was an epic battle (against Tiafoe). I didn't really do much today and I felt like my energy was a little flat today early on.

"It's understandable - I'm only human - but my adrenaline for the final is going to be right there. I'm super excited for it."

Had the ATP not stripped Wimbledon of rankings points in objection to the All England Club's banning of Russian and Belarusian players because of the invasion of Ukraine, Kyrgios would have regained his place in the world's top 15.

Instead he remains at No.63 and continues to make a mockery of the men's rankings, which ridiculously also have Djokovic at world No.6, the Serbian superstar's lowest position in 15 years.

Kyrgios's run in Washington guarantees the 27-year-old a rise to at least No.42 in the world and he's projected to climb to 37th if he lands a seventh pro title.

With big events coming up in Montreal and Cincinnati, Kyrgios is on track to secure an all-important seeding for the US Open starting on August 29 in New York.

with AAP

Click here to sign up to our newsletter for all the latest and breaking stories from Australia and around the world.