Juventus are ready to kickstart the new season reinforced by at least two key signings and hoping to claim a first hat-trick of consecutive titles in Italy's Serie A since the 1930s.

But the domestic aims of Antonio Conte's side, virtually untouchable last season when they triumphed with a nine-point cushion on Napoli, could be kept in check by Napoli, AC Milan and Fiorentina.

And a number of other factors, according to observers.

Juventus have won the 'scudetto' the past two seasons under Conte and begin the season on a high, away to Sampdoria Saturday, a week after routing Cup holders Lazio 4-0 in the Italian Super Cup.

Despite forwards Carlos Tevez and Fernando Llorente arriving to reinforce what appeared to be the only chink in Juve's armour, some believe the club may struggle to claim a third consecutive title for the first time since a five-title winning streak between 1931-1935.

Firstly, Conte wants to see Juve back challenging for Champions League glory.

Juve suffered a 4-0 aggregate humbling by eventual winners Bayern Munich at the quarter-final stage last season.

While Conte admitted it could be a long wait, saying: "The way things are right now, I don't see any Italian teams winning the Champions League for the next several years", some believe a more intensive push in Europe could prove costly.

"If Juve lose some of their intensity, they could become vulnerable," former Fiorentina, Milan and Napoli 'keeper Giovanni Galli told Gazzetta dello Sport newspaper.

Juve have several ageing stars, such as goalkeeper Gianluigi Buffon and midfielder Andrea Pirlo upon whom the imminent pressure from this season's Champions League, as well as next year's World Cup, could weigh.

And former Torino and Lazio 'keeper Luca Marchegiani said: "In Italy, winning three seasons in a row is not easy. Then there's the World Cup, and that could have an impact on veteran players, like Pirlo."

The no-nonsense Conte already appears to be convinced by the on-field efforts of Tevez, but the season is still young and the Argentine's past troubles under Roberto Mancini at Manchester City are still fresh in the memory.

Llorente, meanwhile, was hailed as a great signing by the club when he put pen to paper at the start of 2013 in anticipation of the new season.

But having already been sidelined after struggling to adapt to Conte's tactical systems, the towering Spain international could be used sparingly, with Tevez expected to be paired initially with Mirko Vucinic.

Rival teams would only be too happy to upset Juve's plans to become the first team since Inter, five-time consecutive winners in 2006-2010, to claim three successive championships.

AC Milan, champions in 2011, are hoping to make amends for the mighty gap which saw them trail Juve by 17 points after just 12 games last November before a late fightback allowed them to snatch third place.

Key midfielder Riccardo Montolivo, who has taken over the captain's armband from ousted skipper Massimo Ambrosini -- now at Fiorentina -- believes Milan have now digested losing the backbone of their squad prior to last season.

"We are more of a team than we were a year ago. We are stronger and we feel ready for the season," said the Italy international.

Mario Balotelli remains the Rossoneri's key striker ahead of Italy teammate Stephan El Shaarawy, but on occasion last season the pair had compatability problems and it remains to be seen how and to what extent coach Massimiliano Allegri tinkers with his formation.

Last season Napoli came close to contending a first scudetto since the heady days of Diego Maradona in the 1980s and early nineties and with Rafael Benitez at the helm, only months after the Spaniard led Chelsea to the Europa League crown, they will be looking to make their challenge a more consistent one.

For some pundits, Napoli and Fiorentina -- who recently strengthened with the acquisition of German striker Mario Gomez from Bayern Munich -- could be Juve's closest challengers.

Galli added: "I still can't separate the top teams, but on paper Fiorentina and Napoli seem the teams most likely to threaten Juventus."

Napoli lost striker Edinson Cavani to Paris Saint German barely two months after he finished as Serie A's top scorer (29 goals) and have replaced the flashy Uruguayan with Gonzalo Higuain from Real Madrid.

Although Higuain was used sparingly last season at Real, where the Argentine played second fiddle to Frenchman Karim Benzema, former Bologna player Giancarlo Marocchi believes both Higuain and Gomez will be desperate to show their best.

"Their qualities are already well known, but they have changed leagues and will want to show exactly what they can do in Italy," said Marocchi.