Serena Williams reached her fourth final of the season by taking the last eight games to beat Andrea Petkovic 7-5, 6-0 on Saturday in the Bank of the West Classic.
The top-seeded and top-ranked Williams is 3-0 in finals so far in 2014, winning titles at Brisbane, Miami and Rome.
Against the ninth-ranked Petkovic, Williams wasted four break points in the final game of the first set before eventually converting her fifth.
In Sunday's final at the hard-court tournament, Williams will face Angelique Kerber or Varvara Lepchenko.
Petkovic was trying to become the ninth player — and first since 2010 — to beat both Venus and Serena Williams in the same tournament. Petkovic eliminated Venus in the quarterfinals Friday.