Their match, which started late Monday and ran past midnight, ended too late for May-Treanor to blow out the pirate candle on her actual 35th birthday, but it was a victory worthy of a party.
"We're celebrating on California time," Walsh Jennings said early Tuesday morning in London after the 21-14, 21-19 victory over Czechs Marketa Slukova and Kristyna Kolocova.
It was the 16th consecutive Olympic victory for the two-time gold medallists . The Americans, who have never lost a set in three Olympics, fell behind 18-15 in the second before tying it 18-all.
The Czechs again took the lead but May-Treanor hit one off the heel of her palm into the far corner, then Slukova left two short of the net.
"We know that we can beat them," said Kolocova, who lost in the third set 15-13 to May-Treanor and Walsh Jennings in Rome earlier this summer. "But I think we are still not strong enough to change in our heads that it is possible."
Americans Jake Gibb and Sean Rosenthal lost to Poland in pool play earlier Monday night, the first loss for the American men or women in beach volleyball at the London Games.
Grzegorz Fijalek and Mariusz Prudel, the No. 7 team in the Olympic rankings, beat the Americans 21-17, 21-18. The U.S. team is 1-1 in pool play with one remaining match on Wednesday; they might not need to win, but a victory could be necessary to avoid relegation to a "lucky loser" playoff.
"It is a big game against Latvia," Rosenthal said. "We'll be ready."
The Americans had beaten the Polish pair in straight sets at the Berlin Grand Slam event in mid-July.
"They made some big adjustments from the last time we played them," Gibb said.
Fijalek said it was obvious they needed to make changes if they were going to compete with the Americans, who were No. 4 in the world coming into the games.
"Of course, because we lost very easy in Berlin," he said. "We watched that game many times. We played new beach volleyball."
Earlier in the night session, Sascha Heyer and Sebastian Chevallier beat Russia on a disputed call that ended with Russian Konstantin Semenov arguing with the referee and drawing a yellow card.
After winning a 31-minute first set — as long as some entire matches — 28-26, the Swiss lost the second 21-18. They trailed 13-11 in the 15-point third set before scoring three straight points.
On set point, Heyer's serve went untouched to the deep part of the court, and the linesman signalled it out. But the referee climbed down from her stand, walked over to examine the ball mark, climbed back to her stand, and signalled the winning point for the Swiss.
Semenov began arguing and didn't stop, even after the referee, Catriona Tweedie of Austria, held up the yellow card. Points can be awarded the other team for yellow cards, but at the end of the match it is meaningless.
"I'm not happy at all with the decision of the judge," said the other Russian, Serguei Prokopiev. "We play at such a high level, and this has happened before."
The Swiss also thought it was out until seeing the replay.
"I went back to get the next (serve), but suddenly my partner comes up to me and starts hugging me," Chevallier said. "Now we were lucky, and maybe two days from now we'll be unlucky."
Earlier Monday, defending bronze medallists Zhang Xi and Xue Chen recovered from an opening loss to beat Switzerland. The Chinese pair was upset in the very first match at Horse Guards Parade but would likely advance with a victory over Greece on Wednesday.
In other women's action Monday, medal favourites Juliana and Larissa of Brazil beat Katrin Holtwick and Ilka Semmler of Germany and Czechs Hana Klapalova and Lenka Hajeckova beat Natacha Rigobert and Elodie Li Yuk Lo of Mauritius also won in two sets. Maria Tsiartsiani and Vasiliki Arvaniti of Greece beat Russia's Anastasia Vasina and Anna Vozakova 18-21, 21-13, 15-12.
In the men's competition, straight set victories went to Martin Spinnangr and Tarjei Viken Skarlund of Norway over Canadians Joshua Binstock and Martin Reader; Aleksandrs Samoilovs and Ruslans Sorokins of Latvia over Freedom Chiya and Grant Goldschmidt of South Africa and Ricardo Santos and Pedro Cunha of Brazil over Britain's Steve Grotowski and John Garcia-Thompson. Germany's Julius Brink and Jonas Reckermann beat Wu Penggen and Xu Linyin of China 13-21, 21-19, 15-8.
Also on HuffPost