Italy's Vincenzo Nibali warned that his confidence was growing as he returns to defend his Milan-San Remo title in the first 'Monument' spring classic of the season through north-western Italy on Saturday.

The 2014 Tour de France winner, nicknamed 'The Shark,' made a late solo break on the final ascent of the Poggio to win the 291km (181 mile) race last year.

Nibali's audacious attack with 6.5km to go remains one of the highlights of last season.

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But the Bahrain-Merida rider will have his work cut out in a field which includes road world champion Alejandro Valverde of Spain and previous winners, France's Arnaud Demare (2016), Germany's John Degenkolb (2015) and Norwegian Alexander Kristoff (2014).

"I'm happy with the signals I received from the Tirreno-Adriatico, because they showed my fitness is improving," said Nibali, who finished 15th in the 'Race of the Two Seas'.

"The San Remo is perhaps the most difficult race to interpret and this is its great charm," said the Italian.

"It's always hard to win a race like this and winning it twice is even harder.

"In the last race the result was not as I expected, but I feel better and better now.

"It will not be easy to repeat last year's task, but I will do my best."

But 27-year-old Demare, who finished third last season, warned that reclaiming the Milan-San Remo was one of his main objectives of this season.

"It's a race that's within my ability, I've already won it, I've done a podium, I finished sixth ...," said Demare.

"Even if I didn't raise my arms (in victory) on the Paris-Nice, I regained my form and confidence.

"It's a race in which I often compete, and one day, for sure, I will win again," warned the French rider.

France's Romain Bardet returns for the first time in six years, saying he had been inspired by Nibali's exploits last year.

"The fact that Nibali won was another stimulus for his decision to return," his coach Jean-Baptiste Quiclet said.

Bardet, the 2016 Tour de France runner-up, added: "I'm not expecting anything in particular. I'm not ruling anything out, but I'm heading in without pressure. I will let myself be guided by my instinct."

Viviani, Alaphilippe On A Roll

Italy's Elia Viviani has been the quickest sprinter this season with his Deceuninck-Quick Step French teammate Julian Alaphilippe also in form, winning the Strade Bianche in Tuscany and two stages of the Tirreno-Adriatico.

Bora-Hansgrohe pair Peter Sagan and Sam Bennett are also in the mix. Irish rider Bennett won two stages at Paris-Nice last week.

Britain's Mark Cavendish has withdrawn as he recovers from Epstein-Barr virus, pulling out of the Paris-Nice last week on stage two, with other absentees 2017 winner Michal Kwiatkowski of Poland and Germany's Marcel Kittel.

Australian Caleb Ewan (Lotto-Soudal) came second to Nibali last year, and is looking to go one better this time.

The race starts in Milan with a long stretch on the Po Plain before the riders cross Passo del Turchino to reach the Mediterranean.

The route continues on the flat to the Capo Mele, Capo Cervo and Capo Berta, a trio of climbs to warm up for the final combination of Cipressa and the famed Poggio, which is crested with 5.4 kilometres remaining.

A highly technical descent brings the riders to the finish line at Via Roma in San Remo's historic centre.