CASTELRAIMONDO, Italy (VN) — Cycling’s grand-tour stars will fight their first big battle on the WorldTour stage Sunday in Tirreno-Adriatico, along the 16.1km road up Monte Terminillo.

“It’s the principal stage that is going to mark this race,” said Alberto Contador (Tinkoff-Saxo). “It’ll give me and the others an idea of whether we are in form on the climbs.”

Added Rigoberto Urán (Etixx-Quick Step): “Tomorrow will be the stage that could decide this entire Tirreno. I’m very good, and I’m improving well.”

Sky’s Wout Poels leads the Italian stage race as it cuts through central Italy towards the east coast and the finish Tuesday in San Benedetto del Tronto. He escaped on the Crispiero climb on Saturday and rode solo to win 7km later in Castelraimondo.

“I’m in really good shape,” Poels said. “I’m really confident to defend the jersey and to keep it.”

Behind the blue jersey, a who’s who of grand tour racing is tightly packed in the classification, from Urán at 17 seconds to 2014 Giro d’Italia winner Nairo Quintana (Movistar) at twice that. The 2014 Tour de France champion, Vincenzo Nibali (Astana), sits at 31 seconds with last year’s Tirreno-Adriatico winner, Contador, at 32 seconds.

The only big name missing is Sky’s Chris Froome, who had to pull out two days beforehand due to a chest infection. He is at home in Monaco and recovering.

The Monte Terminillo climb in Italy’s Lazio region last featured in a big race in 2010, when the Giro d’Italia visited and Chris Anker Sørensen won. The first half is the worst, averaging 8.1 percent and kicking up to 12 percent. But the second half, due to the distance beforehand (the stage covers 197km) and the altitude (above 1500 meters), will take its toll.

“When it’s not so steep it’s easy to sit on the wheel,” Tinkoff team manager Bjarne Riis said. “On paper, it’s a climb for Nibali.”

Nibali, however, is suffering, perhaps from the 1-2 extra kilograms (2.2-4.4lbs) he is carrying. The Italian was not able to stay with the best riders on Saturday when the race climbed the smaller Crispiero climb at 583 meters and chased desperately to try to rejoin. He finished seven seconds behind the main group. After the stage, perhaps upset, he refused to speak to the press.

“I’m going to keep my eyes open on Terminillo because if I see an occasion, I’ll take it. I’m not just here to watch a bike race,” Nibali said before Saturday’s stage.

“Contador, though, is the one to watch. We know he’s in good form, he’s started very strongly at the start of the season in Ruta del Sol. His team also proved to be very strong helping Peter Sagan on Friday.”

The only dark horse is Nairo Quintana (Movistar). He is racing his first 2015 event in Europe after a crash in the Colombian championships forced him to skip Spain’s Ruta del Sol.

“I’m starting to get into my rhythm again and I feel good. I don’t know exactly where I stand, but I think I’m on good ground, and I hope it’s at the right level for tomorrow,” Quintana said.

“I suffered a good knock in that crash, but I’m okay, I’m not bothered on the bike, and I’m going as normal now.”

Making the test even harder, the forecast calls for snow and chilly temperatures.

One outsider to watch is second-year professional Adam Yates (Orica-GreenEdge).

“Rain and bad weather,” he said. “I’m from England, it’s not going to bother me.”