STANFORD, Calif. — Venus Williams is having such a blast with her tennis again at age 36, she has many more tournament titles in mind before she's done.

Her next chance comes Sunday in the Bank of the West Classic — with a shot at adding a 50th singles championship to her decorated career.

The top-seeded Williams ran all over the court to extend long points and overcame her inconsistent serve before a dominant tiebreaker, holding off tenacious fellow American Alison Riske 6-1, 7-6 (2) on Saturday night to reach the final at Stanford.

"It's been a lot of fun. It's been a lot of work. It's been a lot of inspired opponents I've played. It's not like they just rolled over. They tried to win and some of them almost beat me, and some of them did beat me," she said, chuckling. "That's the wonderful part, stepping up and looking forward to going to these matches and feeling excited about it."

When Williams mastered her serve, she clocked one at 120 mph.

Then, with a chance to close out the match, she committed three straight double-faults.

Leading 5-4 in the second set with a chance to close it out, Williams squandered a pair of match points when she committed three straight double-faults. Even when Williams missed her first serve, the big kick on the second attempt regularly set up her up to dictate points early in the match before she struggled to stay in rhythm in the second.

Williams breezed to take a quick one-set lead until Riske found a groove and returned well. She dug out shots with her strong baseline game to keep pressure on Williams, who looked like vintage Venus for much of the 1-hour, 39-minute match on an especially hot summer night for the Bay Area.

Once she reached the tiebreaker, Williams told herself to leave those struggles behind.

Williams advances to Sunday's championship and will face Johanna Konta, who beat Slovakia's Dominika Cibulkova 6-4, 6-2 in the first semifinal to reach her first career final. Konta also became the first British woman to reach the championship match at Stanford since Virginia Wade was runner-up in 1981.

The 36-year-old Williams has said this week that her strong run to the Wimbledon semifinals this month fueled her to get back on the court at every chance. She won the last of her 49 singles titles in Taiwan in February.

"She's really remarkable," Riske said. "I feel she gives a lot of hope to a lot of players for the longevity aspect."

Williams reached her eighth final at Stanford, second of 2016 and 80th of her career. With this week's strong showing, her ranking will move to No. 6 for the highest she has been since Feb. 14, 2011.

She is a two-time Stanford winner, with her last victory coming here in 2002 against Kim Clijsters. She also won the doubles title with sister Serena in 2009 and has been runner-up five times.

Winning again in the Bay Area where she has had so much success already would mean a lot.

"That would be really, really wonderful and I hope I can achieve it," she said before a swift departure to rest up for Sunday.

Serena Williams was the last American to make the Stanford final two years ago, as Angelique Kerber beat Karolina Pliskova last year.

Riske, playing her eighth career semifinal after reaching last year's quarterfinals playing her first main draw of this tournament, received credit from Williams for her gutsy play and pushing until the very end.

"It was kind of a challenge to me to see if I could be a victor on the longer points," Riske said. "It was a great experience. Always playing against Venus is a special thing."

The third-seeded Konta, in her debut in this tournament, rode her strong service game to the title match of the Bank of the West Classic on a scorching-hot day on Stanford's campus. She won 27 of 29 first-serve points — 93 per cent — and 73 per cent of her second-serve points.

Konta stunned Williams with the straight-set victory in the first round at this year's Australian Open.

"I'm really happy to have come through that and to be into my first final," Konta said. "I'm really happy it's here in California, where the weather is unbelievable."