Kyrgios's straight sets win over world No.10 Daniil Medvedev earned him the Washington Open title - his second ATP Tour 500 series title of the year.

He'll climb to world No.27, putting him in line to be a seed at the upcoming US Open, after he overcame a back spasm to beat the Russian third seed 7-6 (8-6) 7-6 (7-4).

Kyrgios served 18 aces, including one on match point when he asked a crowd member where to hit it for the third successive match.

He backed up his semi-final victory over Stefanos Tsitsipas with his second career win over Medvedev.

It improves his win-loss record against top-10 opponents this year to 5-1 - a winning percentage of 83, the best on the ATP Tour in 2019.

The 24-year-old said it meant more than just the win.

"It's amazing. Where I was six months ago, some of the things I was doing, I was just putting myself in a really tough situation and to respond like this having incredible support, it's amazing," Kyrgios told ESPN.

"I have people behind me backing me. They never lost faith in me even though I lost it in myself.

"This week means a lot. Obviously it's great to get the win, but I've proved to myself and a lot of people that have backed me that I still have it and can still produce at the highest level."

Kyrgios was gracious in victory, praising Medvedev as one of the most consistent players on the tour and also as a role model.

The pair will meet again in a few days if Australia's highest-ranked male gets past Kyle Edmund in his opening round of the Montreal Masters.

Eighth-seed Medvedev has a first-round bye and will face the winner in the second round of the Masters 1000 event.

"All props to Daniil. He's one of the most consistent players there is on tour and he's so young," Kyrgios said.

"His career's just begun, he's younger than me, so to think about all the great things he's going to achieve is pretty scary.

"This week's been one of the best weeks of my life from a tennis perspective. I feel like I've grown as a person and I'm getting better every day."

Neither Kyrgios or Medvedev faced a break point in a match dominated by the server.

After a quiet first set, Kyrgios came to life in the second having received treatment on his back between sets.

He saved his first under-arm serve until the second set, showcased his array of tweeners, including a lob and a drop shot, hit a stack of winners and held his nerve when it mattered as some Medvedev unforced errors in the tiebreakers proved decisive.

While the win returned Kyrgios to the top 32 and a potential seeding at the US Open in three weeks, his main focus was on improving himself off the court.

"It's important [but] at the end of the day I don't care about rankings at all," he said.

"I just want to grow as a person, as a human, and if that comes along the tennis player will come with it.

"That's all I can do, just small habits every day trying to get better."

Following his semi-final win over Tsitsipas, Kyrgios hoped he was an inspiration to children.

"Growing up, I was a very overweight kid. Got told by coaches, teachers, that I wasn't going to be very good at what I chose to do, which was tennis," Kyrgios said.

"And I think people can just relate to people telling you can't do anything, and I am feeling I am proving a lot of people wrong.

"I have beaten one of the best tennis players in the world, and I'm doing it my way. And I am never going to stop doing that.

"I think people can draw inspiration from that. I think you don't listen to anyone, just back yourself and believe in yourself, and that's all that matters." with AP