WIMBLEDON, England - Venus and Serena Williams have a busy schedule today.

First they'll be on opposite sides of the Centre Court net, vying for the Wimbledon singles title - their seventh all-in-the-family final at a Grand Slam tournament, but first since 2003.

Then they'll pair up to play in the women's doubles final, a berth they earned by winning in the semifinals yesterday.

"This is what we've been aiming for," Venus said. "We haven't reached this achievement in a few years now."

She is trying to win her fifth Wimbledon championship and second consecutive. The last woman to successfully defend her title at the All England Club? Serena, who won the tournament in 2002 and 2003, beating Venus in each final.

The second of those was the last time there was a Williams-Williams title match anywhere. Serena holds a 5-1 edge in Grand Slam finals, and 8-7 overall.

Asked about the gap between their all-sister championship matches, Serena said: "The opponent hasn't gotten any easier, that's for sure. So it's going to be a battle again. That's just how it is."

For the sisters, this can't be easy, heading on court knowing a victory for one translates into a loss for the other.

But in the time since that 2003 Wimbledon final, the sisters and other family members say, Venus and Serena have become closer. Venus is now 28, Serena 26.

"We share even more things together off the court. We definitely rely on each other's advice even more," said Venus, who managed to get past the quarterfinals at only one tournament all season before Wimbledon. "We both now know our roles in the relationship and we support each other."

That, they say, could make for a less-awkward match than some of their earlier encounters were.

It's been rare to see either Williams produce against her sister the same sort of searing serves and big groundstrokes they come up with against anyone else.

The grass courts at the All England Club seem to bring out the best in both. Remember, at the previous Grand Slam tournament, the clay-court French Open, Serena and Venus lost in the third round.

Since 2000, 11 of the 18 Wimbledon finalist slots have been filled by one Williams or the other. Today's final will be the eighth in the past nine years at Wimbledon with at least one Williams, and neither has lost a single set so far in the 2008 tournament.

They own a combined 14 Grand Slam singles titles - Serena leads with eight - and also have earned six Grand Slam doubles titles together. They will have a chance to add to the second today when they face Lisa Raymond of the United States and Samantha Stosur of Australia.

"It's good practice for our singles," Serena said. "We're just enjoying every moment."

The sisters advanced to the doubles final by beating Nathalie Dechy of France and Casey Dellacqua of Australia 6-3, 6-3. Then Venus and Serena sat next to each other for a joint news conference, occasionally whispering back and forth.

When they look up at the players' guest box for support today, they'll be searching for the same eyes, those of their mother and co-coach, Oracene Price, and sisters Isha, who arrived during the tournament's first week, and Lynne, who was going to travel from California yesterday. Someone they won't see is their father and co-coach, Richard Williams. He caught a flight home to Florida because he can't stand to watch his daughters play each other.

"He said he did his job, and his job was done, so I guess he's feeling good," Serena said. "No matter what happens, he's for sure going to be a winner."