Stephanie Gilmore has missed a golden chance to spark her World Surf League season, losing in the final stages of the MEO Pro semi-finals in Portugal to Lakey Peterson.
The seven-time world champion paired 6.5 and 5.5-point waves in the first five minutes of their early-morning heat at Supertubos to apply the pressure.
But the American fired back with a heat-best 6.77 and then, with less than two minutes on the clock, produced a 5.57-point ride to pip Gilmore 12.35 to 12.
It was the third consecutive cliffhanger for the Australian, who had beaten compatriot Sally Fitzgibbons and then France's Johanne Defay to reach the final four.
The semi-final exit is a blow to Gilmore's hopes of reaching the season-ending five-person finals after she missed the season opener in Hawaii when she tested positive to COVID-19.
Peterson will surf against the winner of Carissa Moore and Tatiana Weston-Webb - last year's top-two - in the final.
Griffin Colapinto, who scored the season's first perfect 10 to reach the final four, will be tested by two-time world champion John John Florence in his semi-final later on Monday.
Brazilian duo Italo Ferreira and Filipe Toledo will battle for the other place in the final.
The Championship Tour next moves to Australia with Bells Beach and Margaret River hosting events in April.
