Neither powerhouse Filippo Ganna nor overall favourite Jonas Vingegaard were able to overcome the effort of Spain's Juan Ayuso at the opening time trial of Tirreno-Adriatico in Italy on Monday.
Ayuso (UAE Team Emirates) bettered Ganna (Ineos Grenadiers) by just one second on the short, sharp test, with Jonathan Milan (Lidl-Trek) sprinting home to finish third.
Vingegaard (Visa-Lease A Bike), despite sporting a seriously avant garde new aero helmet, was left trailing in ninth position, 22 seconds down on the Spanish rider.
The 10km stage was based on Lido di Camaiore not far north of Pisa, and took riders on a flat but occasionally technical blast up and down the Tirrenian coast.
"I think everybody knew that Ganna was going to be the big rival," said Ayuso, who endured a long wait to see home late starter Ganna, having set his own mark early.
"At the intermediate time check he was there, and then in the final until the last second we didn't know," he added.
"It's a very emotional victory and a very special one, and it gives good morale and good motivation for the week ahead."
Ayuso saved himself for the headwind return leg, he said, and after setting a good time at the intermediate, he was confident he would show well at the finish.
Asked whether Vingegaard should still be regarded as the favourite, he said: "I don't know if he's the favourite, but for sure he's going to be one of the toughest rivals we have in this race. It's good to start this way, to have this time ahead of him, because it's going to be very very hard to beat him."
Ganna, for his part, didn't have a great deal to say, only commenting that he had been happy with his ride and he would keep on following the plan.
The race proceeds tomorrow with a hilly outing down the coast. The route will take riders 198km south, from Camaiore to Follonica. On the way they will encounter the sizeable climb of Castellina Marittima; coming halfway through the stage it is unlikely to play a role in the GC battle, although it is a potential launchpad for a breakaway.
Things hot up later in the week with mountainous stages from Thursday to Saturday, with a final flat stage based on San Benedetto del Tronto to finish the race on Sunday. More on the route can be found here.
RESULT: STAGE 1: LIDO DI CAMAIORE > LIDO DI CAMAIORE 10KM TT
1. Juan Ayuso (UAE-Team Emirates) 10km in 11.24
2. Filippo Ganna (Ineos Grenadiers) at 1sec
3. Jonathan Milan (Lidl-Trek) at 12sec
4. Ethan Vernon (Israel-PremierTech) at 13sec
5. Josef Černy (Soudal-Quick Step) at 14sec
6. Søren Wærenskjold (Uno X-Mobility) at 15sec
7. Antonio Tiberi (Bahrain Victorious) at at 17sec
8. Kevin Vauquelin (Arkéa-B&B Hotels) at 18sec
9. Jonas Vingegaard (Visma-Lease A Bike) at 22sec
10. Romain Grégoire (Groupama-FDJ) at 22sec
GC AFTER STAGE ONE:
1. Juan Ayuso (UAE-Team Emirates) 10km in 11.24
2. Filippo Ganna (Ineos Grenadiers) at 1sec
3. Jonathan Milan (Lidl-Trek) at 12sec
4. Ethan Vernon (Israel-PremierTech) at 13sec
5. Josef Černy (Soudal-Quick Step) at 14sec
6. Søren Wærenskjold (Uno X-Mobility) at 15sec
7. Antonio Tiberi (Bahrain Victorious) at at 17sec
8. Kevin Vauquelin (Arkéa-B&B Hotels) at 18sec
9. Jonas Vingegaard (Visma-Lease A Bike) at 22sec
10. Romain Grégoire (Groupama-FDJ) at 22sec
