The five-times Olympic champion helped the United States to win the opening event, the 4x100 medley relay, against the World All Stars with a split of 58.33sec for the butterfly leg.
She then captured the 100 metres butterfly in 58.72, the 12th-fastest in history, only minutes before switching disciplines and anchoring the 4x100 metres freestyle relay quartet to victory by 0.39sec. The final relay win was sufficient to give the US the match 65-57 and keep them on course for the gold medal today. The Americans will meet Germany, who defeated China 80-42.
Thompson said: "The last five metres I felt like that guy in Saving Private Ryan, all slow motion, a blurry daze where you can't figure out what's going on.
"I was just dead, somehow I made it to the wall, luckily I was there first. I knew it was going to be difficult, but I had no clue it was going to be this difficult. I was just hoping I would survive this whole experience."
The South African double Olympic champion, Penny Heyns, won the 100 and 200 metres breaststroke in 1:08.14 and 2:27.98 respectively.
The Olympic 200 metres freestyle champion, Franziska van Almsick, won her gold medal event plus the 100 metres butterfly for Germany.
Michelle Kwan, silver medallist at this year's Nagano Olympics, led after the ice dance short programme from the world silver medallist, Maria Butyrskaya. The American teenager was greeted with thunderous applause which reached a crescendo as she finished with a flourish. The Russian Victoria Volchkova, who turned 16 on Thursday, was lying third in her first senior competition.
In the boxing semi-finals, the American flyweight Roberto Benitez celebrated his 18th birthday with the biggest win of his career. Benitez, one of three US teenagers to advance to the finals, outpointed the Armenian Vakhtang Darchinyan.Reuse content