Manuel Pellegrini
Manuel Pellegrini took Malaga above and beyond what was expected of them.

Everyone loves an underdog. It is a undeniable fact and a phrase which is often used within football. Why support the team that is expected to be a success when you can cheer on the plucky side that you know, in your heart of hearts, probably stands no chance.

Bayern were undoubtedly the success story this season, and deservedly so, with the side making up for past disappointments with a season that could certainly be considered perfection.

But those sides who overcame adversity, and made something out of nothing, are always appreciated by fans the world ove. Perhaps just as much as the sides that have achieved all the glory.

As the season comes to an end, and transfer rumours take over the sporting horizon for the next two or so months, IBTimes UK chooses to live in the past for a few moments and take you through five of the season's heartfelt stories across the European continent.

Malaga

A side that have been swindled by owners promising money and not delivering, and losing their best player in Santi Cazorla last summer, Malaga were not seen as much of a threat in either La Liga or the Champions League. But the side pulled together in the sight of adversity, topped their group in the initial stages of the European tournament, and thanks to Manuel Pellegrini, achieved the massive feat of beating AC Milan at home - a highlight of their season. Their progression into the last 16 saw them defeat Porto, and come agonisingly close to the semi finals as they stood 2-1 up against Borussia Dortmund on aggregate going into the final 10 minutes of the second leg of the quarter final. A controversial goal saw Dortmund progress, and after that the Spanish club very quickly unravelled, winning just three games until the end of the season. They still finished a very respectable sixth in the table, though the expected loss of Pellegrini to Manchester City will leave them in a particularly precarious position. But as they've shown, Malaga are capable of rising up when no one expects them to.

Borussia Dortmund

The perennial underdogs to Bayern Munich had overcome their biggest competition in the two previous seasons of the Bundesliga, but as the 2012/13 campaign got underway, it became clear the side had European ambitions on their mind. Jurgen Klopp made us all fall a little bit in love with his eccentric and honest nature, and his description of Dortmund as the 'neutral's dream team' while Bayern were the 'Bond villians' in the lead up to the Champions League final was a good indicator of how many across Europe felt preparing to watch the game. Bayern won, deservedly, sealing the perfect season, and now look set to pillage their rivals for two of their best players. But many are certainly hoping that Klopp will achieve the impossible next season, and prove that without the likes of Mario Gotze and [possibly] Robert Lewandowski, he can still compete for trophies.

Marco Reus
Borussia Dortmund captured neutral hearts around the world.

Porto

Porto lost Andre Villas-Boas in 2011 on the back of their stunning Europa League/title win double, and the side lost Hulk a season later, leaving many to question whether they would be up to the competition of Benfica in the 2012/13 season. But while Benfica faltered in the Champions League, Porto came through to the last 16, and despite their rivals looking to be in pole position to win the title, Vítor Pereira's men were able to rise above them in the second last game of the season, with Kelvin's late goal to put the Portistas up 2-1 in perhaps their campagin's defining moment. Their final game appeared a breeze, and after Benfica failed to take home the Europa League trophy, they came home to an empty cabinet on the domestic front as well, sealing one of the most exciting title races across Europe in the 2012/13 season.

Real Oviedo

A small side from the most northern part of Spain, Oviedo were once a huge force in Spain, but owners took their money and disappeared to Cuba, leaving them with a mess seemingly too big to clean up. Last season, they looked on the brink of liquidation, but a left-of-field campaign began to get people around the world to buy shares in the club at around €10 a piece, with advertising through social media, word of mouth and highly respected Spanish football journalist Sid Lowe. The campaign worked, and the club were saved, particularly thanks to Real Madrid, the world's richest man and former players Santi Cazorla, Michu and Juan Mata who all dug deep to help out. The bulk of the shares from football fans came from England, and in April the side staged a 'thank you' game for those who had helped save their club. If you hadn't heard of Oviedo, you surely have now, and the side are now past the dark days of wondering if they'll survive another week to look towards promotion into Spanish football's second division.

Real Oviedo shareholders
Real Oviedo shareholders came from London to see their team play.

Celtic

While Rangers were no longer in sight for Celtic to partake in tough and colourful battles, the side's season appeared to be one of simply going through the motions. And while they finished with the title 16 points clear of second placed Motherwell, it was their Champions League campaign that captured neutral fans' hearts, with the side overcoming European giants Barcelona in a game that seemed to make Neil Lennon happier than winning any trophy. The fans were beside themselves as Celtic defeated Tito Vilanova's men 2-1 during th r group stages and it looked like in that moment that nothing was impossible for the Scottish outfit. A following win over Spartack Moscow sealed their place in the last 16 over favourites Benfica, and though they lost to Juventus 5-0 on aggregate, that one game was certainly the highlight of the season for anyone who enjoys a win for the underdog.