Serena Williams eased into the WTA championships final, thrashing Agnieszka Radwanska 6-2, 6-1 in the semifinals here on Saturday. Maria Sharapova defeated Victoria Azarenka 6-4, 6-2 in the second semifinal.

While Radwanska had had a record-breaking three-and-a-half hour match against Sara Errani the night before, Serena had had a rest day. Not surprisingly, Radwanska admitted that it would be an achievement “just to get to the court in one piece.”

Serena’s groundstrokes soon made it clear that the Pole would have to cover large areas of the court again — and that was something which could not be repeated for long.

Azarenka seals year-end No. 1 spot

On Friday, Azarenka made sure of the year-end world No. 1 ranking, just two matches from the finish of the 2012 season, when she overcame Li Na. The Australian Open champion from Belarus registered a 7-6(4), 6-3 win over the Chinese star.

“It feels great, a dream come true,” said Azarenka, who was also U.S. Open runner-up in 2012 and put together a 26-match winning streak earlier this year.

“I want to play my last matches here and then enjoy being the world number one. I want to focus on this competition, there are still lots of challenges ahead.”

del Potro vs. Federer

At Basel, Juan Martin del Potro reached his second ATP final in succession with a 6-2, 6-2 victory over Frenchman Richard Gasquet at the Swiss Indoors.

The Argentine ended a 67-minute effort with four straight aces as he completed a demolition of the third seed.

del Potro was pleased with his serving as he prepares a possible title in Federer’s hometown.

“It was almost perfect today,” said the South American, who has now beaten Gasquet in five of their six meetings, including three in 2012.

“I was very pleased with my serve. But I still have work to do, I had two double-faults in the second set,” he said in all seriousness.

del Potro swept up the opening set in 31 minutes and traded breaks with Gasquet to start the second.

But, the second seed escaped to a 5-2 lead and showed his serving power against an off-form opponent.

del Potro qualified for the World Tour Finals after reaching the Basel quarterfinals and was helped by the injury withdrawal of Rafael Nadal.

The 2008 Basel semifinalist has won a career-best 61 matches this season and extended his current win streak to eight matches.

Home hero Roger Federer won his 33nd match from his last 34 played at Basel, reaching the final with a 7-5, 6-4 win over Paul-Henri Mathieu.

The results:

At Istanbul: WTA championships: Semifinals: Serena Williams bt Agnieszka Radwanska 6-2, 6-1; Maria Sharapova bt Victoria Azarenka 6-4, 6-2.

White Group: Radwanska bt Sara Errani 6-7(6), 7-5, 6-4; Red Group: Azarenka bt Li Na 7-6(4), 6-3.

At Basel: ATP Swiss Indoors: Semifinals: Juan Martin del Potro bt Paul Gasquet 6-2, 6-2; Roger Federer bt Paul-Henri Mathieu 7-5, 6-4; Quarterfinals: Federer bt Benoit Paire 6-2, 6-2; Mathieu bt Grigor Dimitrov 7-6(2), 7-6(4).

At Valencia: ATP Valencia Open: Semifinals: David Ferrer bt Ivan Dodig 6-4, 6-7(5), 6-1.

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