Backing up from his gruelling workload a day earlier, when he finished off Reilly Opelka then saved five match points in an epic quarter-final win over Frances Tiafoe, Kyrgios dealt with Michael Ymer in straight sets.

Kyrgios produced another imperious serving display to 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.

Yet to be broken all week in the American capital, Kyrgios didn't face a solitary break point against Ymer.

He 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.

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.

The most recent of his six ATP titles came in Washington in 2019 and he'll play Yoshihito Nishioka in his 11th career final hoping to snare another after the unseeded Japanese shocked Russian top seed Andrey Rublev 6-3 6-4 in Saturday's second semi.

And after winning a second doubles title of the year last week in Atlanta with fellow Australian Thanasi Kokkinakis, Kyrgios will look to go back-to-back in the Washington final with American Jack Sock.

Kyrgios and Sock will play Ivan Dodig and Austin Krajicek in the doubles decider following sufficient rest after the singles final.

Australian Associated Press