The mid-2000s Champions League had a lot of memorable storylines, but the blossoming rivalry between Chelsea and Barcelona is definitely up there.
Starting from their meeting in the 2004/05 last 16, the two sides butted heads three more times before the end of the decade, putting on classic after classic after classic.
These were two of Europe's scariest teams at the time. Chelsea were a newborn juggernaut under Jose Mourinho, while Barcelona were an undisputed powerhouse. A real clash of the titans.
To this day, meetings between the two teams can be more than a little feisty, and it all dates back to that first meeting in February 2005.
Chelsea rocked up to Camp Nou and were humbled by an attacking line of Samuel Eto'o, Ronaldinho and Ludovic Guily. The Blues may have taken the lead through a Juliano Belletti own goal, but late strikes from Maxi Lopez and Eto'o handed Barcelona the victory they deserved.
When the two sides met again for the return fixture on March 8, 2005, things went up to a whole new level.
Barcelona firmly believed they were the best team in Europe, so when Eidur Gudjohnsen, Frank Lampard and Damien Duff had the Blues 3-0 up within 19 minutes, they felt shell-shocked. Disrespected. How dare Chelsea embarrass them like this?
A Ronaldinho penalty gave Barcelona a route back into the game, but that wasn't good enough for the Brazilian. He was on track to win the 2005 Ballon d'Or, and big-time players make big-time plays. It was up to him to save the day.
The clock ticked over to the 39th minute and Ronaldinho found himself in some space on the edge of the penalty area. He picked the ball up but had a wall of three Chelsea defenders closing in and the Premier League's best goalkeeper, Petr Cech, watching on from what looked like safety. A goal seemed a million miles away.
Ronaldinho stopped the ball dead in its tracks and then decided to change sport for a few seconds. Channelling everything he knew about Samba dancing, the winger planted his toe in the ground and gave it a few little shakes. Nobody could understand it, and the entire Chelsea defence seemed to stop in awe.
Like a snake charmer mesmerising a cobra, Ronaldinho had the Blues in a trance. They could do nothing but admire what was going on. As the Brazilian himself would later say: "It's like someone pressed pause and for three seconds all the players stopped and I'm the only one that moves."
Within the blink of an eye, Ronaldinho pulled his foot back and lined up a shot, but what he did next had the world in awe.
For a player of such grace, class and elegance, most expected an outside-of-the-boot strike or a rabona, but that's not what he gave us. Instead, he connected with the most beautiful toe punt the world has ever seen.
The gap in which he could see the goal was no wider than a football. If he was to score this, it had to be the most perfect strike of a ball he had ever delivered, and that's exactly what it was.
Cech, John Terry and Ricardo Carvalho all stood by and watched, unable to come anywhere close to the ball. Ronaldinho's magic powers had bamboozled the defence who would only concede 15 Premier League goals that year. It was unheard of.
Chelsea knew they had been on the end of something special, and Terry did manage to make up for it with a late header that ensured the Blues went through to the next round on aggregate, but crashing out of the competition did nothing to tarnish Ronaldinho's reputation.
He did go on to lift the Ballon d'Or and was also named the FIFA World Player of the Year, the UEFA Forward of the Year and the FIFPro World Player of the Year.
This was a man who was on a whole other level to the rest of the world at that point in time, and if you are in any doubt of that, just go watch his goal against Chelsea from March 8, 2005.