The Champions League has finally made its return this week, as the competition entered the knockout stages, with 16 teams competing for a place in the final in Kiev come June.
With the usual suspects tipped to battle it out in the latter stages of the competition, the Champions League has a habit of throwing the tag of favourites out the window in favour of an underdog story.
The tournament has had its fair share of underdog stories down the years and here are nine of the best.
1. Valencia - 1999/00
Although being beaten convincingly in the final against fellow Spanish side Real Madrid, Valencia's route to the final was certainly one that defied belief.
Finishing top of an initial group ahead of Bayern Munich, the Spanish side eventually qualified for the quarter-final stage of the Champions League with an unenviable route ahead of them.
Seeing off a tricky side in the shape of Lazio, they faced Barcelona in the semi-final, with many assuming that the 2000 Champions League final would become an El Clasico.
Instead, Valencia's 5-3 aggregate win against the Catalan side meant there was no El Clasico final, although winning the entire competition proved to be a step too far for Hector Cuper's side.
2. Leeds United - 2000/01
Leeds fans remember fondly the early 2000's and how close the Yorkshire side came to reaching the Champions League final.
Boasting the likes of Rio Ferdinand, Alan Smith and Harry Kewell to name a few, Leeds had some memorable European nights that season, beating the likes of AC Milan and Lazio en route to the semi-finals.
Despite holding Valencia to a 0-0 at Elland Road in the first-leg, David O'Leary's side eventually lost the second-leg 3-0, putting an end to an extraordinary run going toe-to-toe against some of Europe's elite.
3. FC Porto - 2003/04
The 2003/04 Champions League threw up many surprises, namely FC Porto winning the competition.
Led by Jose Mourinho, the Portuguese side followed up their UEFA Cup success the season prior, and with some drama along the way in the shape of a last-16 win against Manchester United, managed to win Europe's greatest club competition.
FC Porto put in a convincing 3-0 win against fellow surprise package AS Monaco in the final that season in a final that no one could've predicted, with a notable mention also going to Spanish side Deportivo La Coruna who stunned the European heavyweights to also reach the semi-finals that season.
4. Liverpool - 2004/05
Arguably the greatest final in the history of the Champions League, Liverpool's run to even reach the final was just as memorable.
A late Steven Gerrard goal in the Reds' final group game against Olympiacos meant they made the knockout stages, before overcoming some of Europe's elite in the shape of Juventus and Chelsea to even make the final.
The final itself was a true underdog story, turning round a three goal deficit against AC Milan in six second half minutes, before winning the game on penalties and capping a truly great European campaign.
5. FC Schalke 04 - 2010/11
Despite not winning the competition, Schalke 04's run to the semi-final was one of the stories of the Champions League that season.
Led by the veteran Spanish striker Raul, along with the emerging talent of Manuel Neuer, the German side topped their group, before beating the likes of Valencia and Inter Milan, before being ousted by Manchester United in the semi-final.
Schalke only managed to finish 14th in the Bundesliga that season, which magnifies the extraordinary achievement of reaching the latter stages of the Champions League that season.
6. Chelsea - 2011/12
Chelsea's success in the Champions League in 2012 was made all the more impressive by their run to final as well their remarkable victory against Bayern Munich.
Struggling domestically, the Blues needed extra time to see off Italian side Napoli in the last 16, before putting in a superhuman effort to overcome the reigning Champions League winners in the semi-final.
The final itself was a true underdog story, as a late Didier Drogba header forced the game into extra-time at the Allianz Arena, before Petr Cech's penalty save meant the game was decided on penalties, allowing Chelsea to win their first Champions League in the club's history.
7. APOEL Nicosia - 2011/12
In what was only their third season competing in the Champions League, APOEL Nicosia shocked everyone by reaching the quarter-finals that season.
Managing to top their group was an achievement in itself, they then faced Olympique Lyonnais in the last 16 stage, with many predicting the French side to overcome the minnows in European football in convincing fashion.
Instead, the Cypriots battled to win the tie on penalties and set up a quarter-final tie against Spanish giants Real Madrid. Although losing the tie 8-2 on aggregate, the fact that APOEL reached the quarter-final was an outstanding achievement in itself.
8. Borussia Dortmund - 2012/13
An all-German final in 2013, Borussia Dortmund made it to their first Champions League final since 1997, when they won the competition.
Dortmund made hard work of making it to the final, needing two late goals against fellow underdogs Malaga in order to reach the semi-finals of the competition.
Facing Real Madrid in the semi-final, the German side shocked the footballing world with a astounding 4-1 first-leg win against Real Madrid courtesy of four goals from Poland star Robert Lewandowski.
Despite losing the return leg 2-0, Dortmund made sure the final in Wembley was an all German affair. Jurgen Klopp's side however couldn't cap their fairytale run with a win, losing 2-1 to Bayern Munich.
9. AS Monaco - 2016/17
The most recent underdog story in the Champions League comes in the shape of French side AS Monaco.
In a spectacular season for Leonardo Jardim's side that saw Monaco wrestle the Ligue 1 title from French juggernauts Paris Saint-Germain, they managed to reach the semi-finals of the Champions League with a young, hungry squad.
Making stars out the likes of Kylian Mbappe, Thomas Lemar and Bernardo Silva whilst being led by a rejuvenated Radamel Falcao, the principality saw off the likes of Manchester City and Borussia Dortmund in the knockout stages, before eventually succumbing to Italian giants Juventus in the semi-finals, losing the tie 4-1 over the two legs.