Despite struggling with the 2,000 metre altitude, world champion Kate Courtney (Scott-SRAM) managed to retain her lead in the overall standings.
Hot, dry and dusty conditions added to the difficulty of this extremely demanding circuit, with rough descents causing numerous crashes, and steep climbs made worse by the thin air. Altitude was a huge factor, with most of the early leaders fading in the second half of the six-lap race.
Courtney and Italian champion Eva Lechner took the lead on the first climb, joined by Sina Frei (Ghost Factory), Anna Tauber (CST Sandd Bafang), Pauline Ferrand Prevot (Canyon Factory) and Catharine Pendrel (Clif Pro). Jolanda Neff (Trek Factory) had a slow start, dropping to more than 40 seconds back in the first few laps.
Pendrel moved into the lead on the steep 'Wall' climb, joined by Frei and Ferrand Prevot on lap 2, and then gradually by Terpstra and other riders, including Neff, who was riding herself back into contention.
As the early leaders faded off the podium, Terpstra moved into the lead, and was caught by Neff on the fifth lap. Behind, Yana Belomoina (CST Sandd Bafang) was riding her way into third and Olympic champion Jenny Rissveds (Sweden), in only her second World Cup since the Olympics, moved up to fifth. Also riding well at altitude was Mexico's Daniela Campuzano, eventually finishing fourth in her first World Cup podium.
At the front, Neff tried an attack on the first climb of the final lap, but Terpstra immediately countered and rode away to win by 38 seconds. Belomoina took third, followed by Campuzano and Rissveds to complete the podium.
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Courtney's lead drops to 75 points over Neff, with Terpstra jumping to third overall from seventh. Tauber moved up one spot to fourth, and Belomoina from ninth to fifth.
Terpstra was unaware that her first World Cup win was, in fact, the first for Dutch woman at the Elite level.
"I didn't think of it when I was racing, but I felt good all week and I knew that I had prepared well for the altitude, which is normally a weakness for me," said Terpstra.
"I didn't expect this, but I wanted to take a risk, so I'm very, very happy. My team had said, 'Don't go too early,' but I thought that if I let Jolanda go down the downhill first, I would have to catch up, so I tried to be first into the downhill, and then I saw I had a little gap, so I gave everything I had, but without overdoing it."
Rissveds, who retired after the Rio Games with what she recently described as mental-health issues from the pressure, made a stunning comeback from starting well down in the field.
"I can't believe it," she said. "My self-confidence had disappeared; it was gone since the Olympics. I couldn't believe that I could come back and be up there.
"After Nove Mesto [the previous World Cup, which was her first race back, where she finished 33rd], I looked around and saw the riders I was with and thought, 'I shouldn't be up here – I'm not one of them anymore.' When you start to think like that, your body shuts down and you can't get out your full potential.
"After Nove Mesto, I started to work on my mind game, and it's incredible what your head can do," she continued. "If you believe in yourself, you can go so far. I don't want to focus on results anymore, because that is one of the things that took me down, but I can't stop dreaming about coming back to [the level I was] when I stopped, and I will keep on working until I can say I'm back at the same level."
