Updated

Misty May-Treanor and Kerri Walsh Jennings are headed to another Olympic beach volleyball final.

It has the chance to be an all-American affair.

May-Treanor and Walsh Jennings survived for a 22-20, 22-20 win on Tuesday over 2008 bronze medalists Xue Chen and Zhang Xi of China in the semifinals at the London Games.

Later, Americans April Ross and Jennifer Kessy were to play Brazilians Juliana Silva and Larissa Franca in the second semi with the winner moving on to the gold medal match against May-Treanor and Walsh Jennings on Wednesday.

May-Treanor, who turned 35 last week, and the soon-to-be 34-year-old Walsh Jennings rallied from behind early in the first set and late in the second to beat their younger opponents under cloudy skies at Horse Guards Parade.

The two-time reigning Olympic champions won the final three points of the match to avoid dropping a set for the second time in a week (and the second time ever at the Olympics).

"They were playing awesome but we made it happen. I'm speechless," said May- Treanor. "I think we played as a unit, so I'm very happy. I had a picture in my head at the beginning of the season of how I wanted us to play, and we're living that picture. But it's not over yet."

They used power and finesse to pull themselves out of an early hole -- May- Treanor's dig saved a key point at the end of a long rally -- and won the first set when Zhang hit into the net.

Later, China built a 17-16 lead in the second set when Xue, 23, followed her 27-year-old partner with a spike.

The point of the match came minutes later when May-Treanor scrambled to save the ball behind the end line and Walsh Jennings tapped it over the net for a drop shot that tied the set at 19.

The Americans saved a set point at 19-20 and May-Treanor's delicate tap into the backcourt made it 21-20. Walsh Jennings won the match with a block at the net on Zhang's spike.

"We played very good, but we didn't do what we could do at the right points. We didn't play to our potential," said Xue. "It was quite hard to defend them. We need to improve on attack."

The men's semifinals were also Tuesday.

In the first match, Brazil's Alison Cerutti and Emanuel Rego beat Latvia's Martins Plavins and Janis Smedins in straight sets 21-15, 22-20.

They will meet either Germany's Julius Brink and Jonas Reckermann or Reinder Nummerdor and Rich Schuil of the Netherlands in Thursday's gold medal match. Those teams are playing the late match Tuesday.