Last night was a real advert for what makes the Champions League so exciting.As Manchester City saw off Monaco in a breathless 5-3 encounter, Atletico Madrid were beating Bayer Leverkusen 4-2, making it the highest scoring day in the knockout stages so far.In fact, City's win over Monaco proved to be the highest scoring first leg of any Champions League tie ever!And during all this action, social media was a frenzy with opinions, jokes, hot takes and admiration.But buried in amongst them all was a cryptic tweet from a player who should very much be enjoying the spoils of European football instead of watching from his sofa.Romelu Lukaku has been heavily linked with a move away from Goodison Park recently, with former club Chelsea believed to be one side interested in making a move for him.The Toffees have certainly had their chances to make it to the competition, but have always fallen short at the crucial time, and should they miss out this term, they may just have to wave goodbye to their best player."UCL is where reputations are build... what a competition What a game," he said.It could simply be an innocuous tweet sent in the excitement of the moment, or it could be something with a little more weight to it.Certainly, Lukaku is coming to an age where he needs to be playing at the absolute top of the game in order to fulfil his enormous potential.It would seem unlikely that he's going to get that at Everton, and the replies to the tweet seem to suggest that everyone is looking into a little more seriously.