KEY BISCAYNE, Fla. -- Talk about a big turnaround from their previous matches. This is clearly a case of one Williams sister being on her game and the other not. Serena defeated older sister Venus 6-2, 6-2 on Thursday in the semifinals of the Nasdaq-100 Open. .

	Pam's Perspective
	Shriver Former WTA Tour pro Pam Shriver provides ESPN.com with in-depth analysis. Shriver, a tennis analyst for ESPN, reached a high ranking of No. 3 in singles play. She won 21 singles and 112 doubles titles, including 22 Grand Slams.

For the first time, Serena was able to maintain her level of play. She served well -- Venus only won one point on her second serve. Also Serena only had 10 unforced errors, which sounds like a lot unless you realize that's only five a set and it's a very clean match for her.

Venus looked like she had been struggling all week. Elena Dementieva could have beaten her in the quarterfinals and she lost a first set to a qualifier, who I'd never heard of, earlier in the week. She just never hit stride all week long.

So if you look at their semifinal from the standpoint of the other players in the top 10 this week, it held up. But with their past pattern of Venus always coming out on top it makes some people skeptical. I'm not one of them, but you have to open it up to some of those who believe perhaps it's Serena's turn to win. I believe Venus is too good of a competitor, though, to let that happen.

Let's face it, it's not like Venus always has her game, and it's not like she always has her second serve. That's her weakness. She lost to Monica Seles at the Australian Open a couple of months ago, to Sandrine Testud in the Middle East, and she lost 6-1, 6-1 to Martina Hingis in the semifinals of the 2001 Aussie Open.

So perhaps this marks a change in the balance of the Williams sisters story. You look forward to the future when they can both play a good match. Until both play their best tennis, there are going to be skeptics. But we'll have to wait a little longer for that to happen.