British third seed Johanna Konta celebrated her first WTA Tour final appearance with a three-set win over former world number one Venus Williams at the Bank of the West Classic.
Konta, 25, went from a set and 4-1 up in the second, to contesting a decider against the top-seeded American, but she regained her composure to secure a 7-5 5-7 6-2 victory in Stanford on Sunday.
After rallying to force a third set, Williams lost her way in the decider as she was denied a 50th WTA title.
Playing in her first final, Konta was not overawed by the 36-year-old seven-time grand-slam champion, breaking Williams for a 2-1 lead.
Williams held off Konta in the ninth game to make the Brit serve for the first set and she the converted the second of two break points to level at 5-5.
Konta broke straight back, however, as she served out the set 7-5, before taking control of the second.
She broke twice in the opening five games for a commanding 4-1 lead, though Williams refused to surrender, recovering both breaks to tie things up at 4-4 as nerves kicked in.
Williams then held serve before leveling the match after breaking again, with Konta looking out of sorts.
But after a marathon opening game, Konta proved too good as she slowly weighed Williams down, going up a double break, a lead she never relinquished, despite almost being broken on three occasions as she served out the match.