Nine in Their Prime: Europe's Undefeated Sides

Following Wednesday night's Paul Pogba-driven 2-1 victory over Bologna, Juventus extended their lead at the top of Serie A by three points.

They are the only Serie A side to remain undefeated in this campaign, having suffered their last league loss in the 2010/11 season.

With that being said, the Old Lady aren't the only undefeated side in Europe. Here are nine European sides who have yet to suffer a loss this season.

Manchester City

The Citizens haven't looked entirely convincing this season, and Roberto Mancini continues to fastidiously tinker with his lineup, but they are now the only Premier league side without a loss.

Later this month, however, they will visit Stamford Bridge, where they have been beaten in the past two seasons.

Shakhtar Donetsk

With Wednesday night's 4-1 win over Hoverla, Shakhtar went 12 points clear in the Ukrainian Premier League, having won all 13 of their matches.

They are now Europe's only major side to have won all of their league games.

Led by Brazilian wonders including Willian, Luiz Adriano and Alex Teixeira, Shakhtar are now undefeated in all competitions in 11 months.

Juventus

The aforementioned Turin side have won nine and drawn one in this campaign, continuing to build on last year's undefeated title-winning season. They have now gone 48 league games unbeaten, and have kept five clean sheets this season.

Their dominance will be tested this month as Internazionale and Lazio visit Juventus Stadium.

Paris Saint-Germain

Fresh from ending Marseille's four-year unbeaten run in the Coupe de la Ligue this week, Carlo Ancelotti's men will aim to remain undefeated when St Etienne visit the Parc des Princes this weekend.

One of the main reasons for the oil-rich side's good fortune is the incredible form of Zlatan Ibrahimovic. A total of 10 of Les Parisiens' 16 league goals this season have come from the prolific Swede.

Benfica

The Portuguese Primeira Liga leaders have yet to win a Champions League match in this campaign, but they are unbeaten domestically, with five wins and two draws.

Yet Jorge Jesus' men will face tough tests in their next two league matches with Guimaraes and Rio Ave.

Porto

Benfica aren't the only undefeated side on the Iberian Peninsula.

Reigning champions Porto are tied on points with their Lisbon rivals at the top of the table, and also have five wins and two draws.

Since losing two-time Liga top goal scorer Hulk to Zenit, Porto haven't suffered in the goal-scoring department. They've put away 10 goals in four league games, with Jackson Martinez remaining prolific.

Ajax

Reigning Eredivisie champions Ajax may be seven points off FC Twente's lead in this campaign, but the fourth-placed side are the Netherlands' only undefeated team of 2012-13, with four wins and six draws.

To continue their streak, Frank de Boer's side will need to defend better away from home. The Amsterdam side have leaked nine goals on five away trips so far.

Barcelona

With the likes of Leo Messi, David Villa, Cesc Fabregas and Pedro all in fine form this season, it's no surprise that the Catalan giants have yet to slip up.

Barca have won eight and only drawn a thrilling Clasico with Real Madrid last month. (Los Blancos, incidentally, are the only side to defeat Barca in the league since February.)

Tito Vilanova's side have scored five goals on three separate league outings so far this season, and show no signs of slowing down.

Atletico Madrid

Joining Barca at the top of La Liga with an identical record are Atletico Madrid.

A total of 10 of Los Rojiblancos' 22 league goals have come from prolific striker Falcao. If they can hold onto the Colombian for the remainder of the season, a top-two finish is not out of the question.

While Diego Simeone's men must be congratulated for their undefeated streak, their next game is a tough visit to Valencia, and they have yet to face either Barcelona or Real Madrid.