WIMBLEDON, England — Venus and Serena Williams are one round away from meeting in another Wimbledon final.

Five-time champion Venus overpowered Agnieszka Radwanska 6-1, 6-2 on Tuesday, and two-time winner Serena followed her into the semifinals with a 6-2, 6-3 win over Victoria Azarenka.

No. 3-seeded Venus will next face top-ranked Dinara Safina, who overcame 15 double-faults and beat German teenager Sabine Lisicki 6-7 (5), 6-4, 6-1 to reach the Wimbledon semis for the first time.

In the bottom half of the draw, No. 4 Elena Dementieva defeated Italy's Francesca Schiavone 6-2, 6-2 to set up a semifinal encounter with No. 2 Serena Williams.

It's the first time since 2006 that all four top-seeded women reached the semifinals at a Grand Slam tournament.

The Williams sisters overwhelmed their opponents Tuesday with breathtaking displays of power tennis, showing why they have dominated on the grass of the All England Club for most of the past decade.

"We definitely upped our levels of game today," Serena said.

Venus, seeking her third straight Wimbledon title, outhit the 14th-ranked Pole from all parts of the court and proved again that she is the dominant female player on grass.

"Do I feel invincible?" Williams said. "I'd like to say yes, but I really do work at it."

Williams had her left leg taped up again but showed no weakness at all as she ripped 29 winners — compared to six for Radwanska — in a match that lasted just 68 minutes on a sunbaked Court 1.

"I can't complain," Williams said. "I'm in the semifinals of Wimbledon, right where I want to be. I just need to take another step forward."

With Venus looking on from the guest box, Serena swept through the first set against the eighth-ranked Azarenka in 26 minutes. After being broken to go down 3-2 in the second, she won four straight games and held serve at love to finish the match in commanding fashion. Serena had nine aces and 26 winners, with only seven unforced errors.

Azarenka had beaten Serena in straight sets in their last match in the final at Key Biscayne, Fla., in April.

"I really wanted to do well today," Serena said. "I didn't do well the last time we played. I was not feeling great. I felt like I really wanted to show up today."

Asked whether she also felt unbeatable at Wimbledon, Serena said: "I don't feel invincible, but I definitely should have the same attitude. I'm going to try to feel that way, too."