Lezak, swimming the anchor leg of the United States’ 4x100-metre freestyle relay, hit the water a half-second after Alain Bernard of France, who came into the race as the world-record holder in the 100-metre freestyle.

“I knew I was going to have to swim out of my mind,” Lezak said, adding: “I had more adrenaline going than I’ve ever had in my life.”

Dragging off Bernard, who was hugging the lane line that separated them, Lezak made up ground, but with 25 metres remaining it appeared as if he would run out of pool. Trailing Bernard by half a body length, Lezak put his head down and surged to the wall.

When the water settled, the giant scoreboard showed that Lezak had out-touched Bernard by 0.08 of a second. Phelps’s pursuit of Mark Spitz’s record of seven swimming gold medals in one Olympics remained alive with a little help from his mates. Lezak’s split of 46.06 seconds was the fastest anchor leg ever, by 0.73, and his personal best by over 1.2 seconds.

“His last 50 metres were absolutely incredible,” Phelps said.

After Lezak touched, Phelps, who swam the first leg, raised his arms and let out a primal scream. Garrett Weber-Gale, who swam second, came up from behind him and swallowed him in a hug.

The US were timed in three minutes 8.24 seconds, shattering by nearly four seconds the world record that their B team had set the previous night. France won the silver in 3:08.32. Australia, benefitting from a world-record setting lead-off swim of 47.24 from Eamon Sullivan, were third.

Bernard, who in a matter of minutes lost the 100 world record to Sullivan and the relay gold to Lezak, was bereft. He broke down in tears in the pool.

Though not well-known outside of swimming circles, Lezak, a native Southern Californian, has a reputation in USA Swimming for being the Mariano Rivera of sprinters. “Jason is the most phenomenal closer I’ve ever seen in my life,” said Cullen Jones, who swam the third leg.

After making the turn, Lezak said he momentarily lost the courage of his convictions. Bernard had a 0.6 of a second lead and Lezak was not sure he could reel him in. “I’m not going to lie,” he said. “The thought really crossed my mind for a split-second, ‘There’s no way.’”

Then he reminded himself that he was representing his country and this was the Olympics and he was not getting any younger. “In five seconds I was thinking all these things,” Lezak said. “And I got a super charge.”

With his surge, Lezak kept alive Phelps’s drive to break Spitz’s record and collect a million-dollar bonus from Speedo. Asked if he would demand a cut if Phelps succeeds, Lezak grinned and joked: “We’ve already talked about that.”

Kitajima’s revenge

Japan’s Kosuke Kitajima settled an old score with US rival Brendan Hansen with an emphatic victory in the men’s 100 metres breaststroke final on Monday.

Kitajima’s relationship with Hansen has been frosty since he was accused of using an illegal dolphin kick when he captured the 100-200 breaststroke Olympic double in Athens in 2004.

The 25-year-old from Tokyo ended the argument at the Water Cube, clocking 58.91 seconds, smashing Hansen’s world record, and becoming the first man to win the event twice.

European champion Alexander Dale Oen of Norway was second in 59.20 and Frenchman Hugues Duboscq clocked 59.37 for the bronze.

More drama

There was plenty more drama in the pool, as Rebecca Adlington won Britain’s first Olympic women’s swimming title in nearly half a century with a last-gasp victory in the 400 freestyle.

Australia’s Libby Trickett overcame an attack of nerves to claim gold in the women’s 100 butterfly. “Before the race I felt as if I was going to vomit I was that nervous,” she said.

Kirsty Coventry of Zimbabwe broke the women’s swimming 100 metres backstroke world record in the semi-finals.