As we approach the finishing line in what has been another drama-filled Champions League campaign, perhaps the most intriguing match-up has arrived for all to see as a certain Spanish surprise take on the side located in the posher stretch of London.
Atlético Madrid - Chelsea is the tie that begins what will be two days of fantastic European action on Tuesday.
Here's what the home's side manager Diego Simeone had to say (courtesy of UEFA.com) ahead of the match.
"We are not the same teams but we have similar characteristics. We have the best defensive records in our respective leagues, we both have good defences and play a direct attacking game. We're both also good at set pieces. These characteristics have led to us each fighting for titles. But we will to assess how the season has been at end. We haven't won anything yet.
We know our strengths and weaknesses: We will try to take advantage of our strengths and disguise our weaknesses. Thibaut Courtois's state of mind is the same as that of all his team-mates. They are all filled with enthusiasm. They know the importance of this match – not just for them, but for the club."
After Friday night's 2-0 triumph at home to Elche, Los Rojiblancos made it 12 unbeaten in all competitions and are the only remaining side to be undefeated in the Champions League. Arda Turan should be available after coming through training having missed out on the win through a groin strain. Diego Costa also came through ninety minutes on Friday after a nasty collision with a post when scoring the previous week at Getafe and should be in contention to start against the side rumoured to be moving in on a summer move for the now-Spaniard.
POSSIBLE BANS?
Emiliano Insua, Koke, Juanfran and Gabi are the quartet in danger of picking up a yellow card and earning themselves a suspension from the return leg at Stamford Bridge. The latter three players in particular, especially club captain Gabi and instrumental to Atletico's side and it would be a travesty to Diego Simeone's plans if he lost any of them. Gabi does a fantastic job in preventing opposition's swarms of attack invading his team's defence with his intelligent reading of the game and in particular with his strong tackles- 110 of them in fact, the 2nd highest completed in all of Europe.
Gabi has been one of Atletico's most consistent performers.
As for Chelsea, here are the musings of Jose Mourinho, again courtesy of UEFA.
"I am not here to talk to you about Atlético's qualities; I have already done that with my players. No team arrives in a UEFA Champions League semi-final without being a very good team and they are no exceptions. To be here they have to be a very good team. We respect them, have studied and analysed them.
I have watched them playing many times. When we got them in the draw, I watched them with keener eyes. I have studied them a lot and have tried to give an idea of what Atlético are about to my players. Any team that is fighting for the championship and in the UEFA Champions League must be an important team.
I don't know if playing the first leg at home or away is an advantage. It's difficult for a UEFA Champions League tie to be decided in one game; not impossible, but it is difficult. I like to play without thinking about that aspect too much. We know that Atlético will try everything to win the game but we are going to try to win it too."
Fabio Borini put a huge dent in Chelsea's title ambitions with a late penalty to end Mourinho's 77 game unbeaten record in the league at the 'Bridge, though some positive news occurred on Monday morning as Petr Čech trained for the first time since his bout of illness ruled him out of Saturday evening's defeat. Unfortunately for the fans of Chelsea winger Eden Hazard was forced to sit out, still struggling with the calf injury sustained in the Blues 2-0 success in the last round against Paris Saint Germain, and the Belgian now looks set to miss out on the first leg at the Vicente Calderón at the very least.
Right-back Branislav Ivanovic is suspended whilst Nemanja Matic and Mohamed Salah are both cup-tied per usual after appearing in the competition with SL Benfica and FC Basel. David Luiz or Cesar Azpilicueta could slot in to Ivanovic's position to replace the Serb with Ashley Cole possibly returning to the side at left back.
Chelsea's Serbian powerhouse's absence could mean a struggle against the likes of Koke and Raúl García.
It will also be a special occasion for Thibaut Courtois, on loan from Chelsea at Atlético, who was cleared to play without any money needed to exchange hands for Courtois' participation as was originally thought. The Belgian star has excelled in his third season on loan in Spain and said ahead of the game:
"I was very relieved (to be able to play)," Courtois told the FIFA website. "For me, the fact that we've drawn Chelsea, like we did in the European Super Cup in 2012, is special, because even though I'm at Atléti, Chelsea are my club too. It's better not to think about it too much though and play like I always do, because if I start thinking, 'Oh, I'd better be careful', then I'll end up playing poorly.
"I want to win trophies here and I'll be an Atleti supporter for these two games, but at all other times I'm a Chelsea fan too.
"I hope they win the Premier League, just not these two Champions League matches. I really hope we can reach the final as we're so close. They're the favourites, but Barcelona were too."
Atlético have never lost at home to English sides – winning five and drawing four – and while Chelsea have won just three of their previous 14 games away to Liga opposition they drew 2-2 on their only previous visit to the Estadio Vicente Calderón on 3 November 2009, and I can't see past Simeone winning this round again over Mourinho. Prediction: Atlético 1-0 Chelsea.
All quotes and facts coming from UEFA.com and Squakwa.