The 2013 Champions League round of 16 had a lot to love about it.
Manchester United and Real Madrid going blow-for-blow at the Bernabeu Stadium; Bayern Munich establishing themselves as potential frontrunners with a huge win over Arsenal at the Emirates. And who could forget AC Milan's stunning upset over Spanish giants Barcelona.
There was clearly plenty of good and enjoyable takeaways from the first leg of these matchups yet, at the same time, each time had it's own disappointments and frustrations.
Some might have been more pronounced than others, but every team had them in their first leg. Read on to see what their biggest disappointment in the Champions League was.