Unics Kazan survived a frenetic 4th quarter comeback attempt from fellow Russian side BC Khimki, to send their best of three series to a deciding game next Wednesday in Moscow.
Kazan, who are looking to defend the title they won in 2004, looked to have the game sewn up by halftime, when they led 45-28. But Khimki staged a second half rally and it was only in the last 50 seconds that Kazan made the game safe.
The naturalised Georgian guard was unstoppable in the second quarter, scorching Khimki for 14 points. Williams was ably assisted by Australian forward Chris Anstey who hit 7 points of his own and after 20 minutes Unics were in complete control.
While Williams dazzled for kazan, Khimki Denis Ershov was quietly putting together his best game of the season for Khimki. The 220 cm, who played for the Russian national team at Eurobasket 2003, was everywhere for Khimki, tallying season highs in points (23), rebounds (13) and blocked shots (6).
Ershov scored 9 points in the third and midway through the period, Khimki had trimmed Kazan's lead to single figures (53-42).
An 8-1 run by Khimki in the final 2 minutes of the quarter put them right back in contention and at the start of the 4th, Kazan led 59-56.
Williams, who had been relatively quiet in the third period (3 points) woke up in the fourth and it was his contribution which finally ended Khimki's challenge.
Williams scored 11 of his game high 35 points in the final 10 minutes, including the game breaking three-pointer.
With just 52 seconds remaining, Kazan led 75-73, but Williams' clutch shot gave Kazan a 78-73 lead at the 30 second mark.
Williams added 9 rebounds to his 35 point haul. Petr Samoylenko had 16 points and 6 rebounds for Kazan.