Nick Kyrgios saved a match point as he overcame top seed Stefanos Tsitsipas to reach the final of the Citi Open in Washington.

The Australian notched up his fourth win against a top-10 player this year as he downed his Greek opponent 6-4, 3-6, 7-6 (7) in two hours and eight minutes.

Kyrgios got off to a flying start, breaking Tsitsipas in his second service game before clinching the opening set.

But the world number six remained undeterred and fought back to level up the match at one set all.

A closely-fought decider ended in a tiebreak, with Krygios firing a service winner to save a match point against him at 6-5 down before eventually triumphing on a second match point of his own.

The Australian will now face Daniil Medvedev, after the Russian ousted lucky loser Peter Gojowczyk.

Medvedev had a more straightforward semi-final clash, needing just 56 minutes to win 6-2, 6-2.

The 23-year-old converted all five of his break-point opportunities and won 78 per cent of his first-serve points during the match.

Meanwhile, Dominic Thiem triumphed on his home soil as he won the Austria Open title in Kitzbuhel.

The world number four saved all six break points he faced to defeat Albert Ramos-Vinolas 7-6 (0), 6-1.