#2 Real Madrid 3-2 Wolfsburg (2015/16, Quarter-Finals)
True world-class players shine through when they're needed most. This is what Cristiano Ronaldo managed to do for Real Madrid. But before all that, Real had managed to lose the first leg against a brave German side who produced a 2-0 victory despite being dominated for most of the game.
Wolfsburg looked set to create a major UCL upset. But Ronaldo had other things in mind and produced an excellent display in the second leg. By the 17th minute, the Portuguese had scored twice for the Spanish giants. The Bundelisga side's attempt to break down Real's attack was to no avail, with Ronaldo completing his hat-trick in the 77th minute.
Real Madrid went on to win the Champions League trophy that season. They did the same next year. Just goes to prove the importance of never giving up.