In the opening quarterfinal match on Tuesday, Venus Williams advanced with a 6-4, 7-6 win against Anastasia Pavlyuchenkova.

But it was Pavlyuchenkova who struck first in the opening set gaining a break advantage and a 4-3 lead. However, the American took little time to strike back and she refused to let up as she took the final three games of the set on the heels of her strong power game.

Venus continued her roll into the second set and had Pavlyuchenkova on the ropes in the second game as she threatened to break. But after more than 12 minutes, the Russian held. The result appeared to spark her as she immediately attacked Williams’ service game and gained her own advantage. The two competitors continued to battle with neither able to gain separation and the set would be decided by a tiebreak.

In the tiebreak, Pavlyuchenkova gained the momentum early as she capitalized off some errors from the Williams forehand. However, the 13-seed would not be denied and strung together a streak of points taking the tiebreak at 7-3 and the match. 

Williams found success attacking Pavlyuchenkova’s second serve throughout the match as the Russian won under 40 percent of those offerings.

With the win, Venus became the oldest Australian Open semifinalist in the open era at the age of 36.

“I’m so excited today,” Williams said. “It was a hard-fought match and she never gave up. I want more. I want to go further and I’m so happy to be in a position to go further.”

The second quarterfinal featured two powerful, first-strike players in Coco Vandeweghe and 7-seeded Garbine Muguruza. And on this day, Muguruza was no match for the American who dominated 6-4, 6-0.

Fans of power tennis were not disappointed as both players slugged it out from the baseline early in the first set. Each was stingy in service games until Vandeweghe found an opening with the Spaniard serving at 3-3. She took the first advantage of the match with a service break and rode her big serve to take the set.

Vandeweghe did not relinquish her momentum and kept the pressure on in the second set striking massive groundstrokes that overpowered the 23-year old. Muguruza appeared stunned at times and could find no answer as Vandeweghe was relentless in her attack, putting the match away. It was one of the more impressive power performances in recent memory.

Vandeweghe finished the match with 30 winners and held the big-hitting Muguruza to just 14, underscoring her dominance.

The win sets up an all-American semifinal as Vandeweghe is set to face Venus.