5 biggest round-of-16 upsets in UEFA Champions League history

#1 Monaco v Arsenal (2014-15)

Arsenal v AS Monaco FC - UEFA Champions League Round of 16

Just as Arsenal were expected to take a big step into the quarter-final phase of the Champions League, having been handed what many expected to be the easiest tie of the last 16, they suffered a crushing and embarrassing defeat.

The warning sides should have been heeded, however. While Monaco had won their group ahead of Bayer Leverkusen, Zenit St Petersburg and Benfica, Arsenal had finished second to Borussia Dortmund. Still, they went into the tie buoyant, having avoided any of the big guns.

That feeling of optimism soon vanished. At the Emirates Stadium, Monaco executed a perfect counterattacking game. Geoffrey Kondogbia gave them the edge before the break and early in the second half, Dimitar Berbatov put Monaco firmly in control.

When Alex Oxlade-Chamberlain struck in stoppage time at the end of the match, it seemed that the crisis had been averted, yet the Gunners self-destructed as they somehow allowed Yannick Ferreira Carrasco, superb on the night, to cap a famous victory for Leonardo Jardim’s side.

Arsenal played much better in the second leg, with goals from Olivier Giroud and Aaron Ramsey giving them a 2-0 win on the night, but yet were still eliminated on the away goals rule.

While such losses have become commonplace for Arsenal fans in recent years, going out to Monaco came as a stunning shock. it may not have been the beginning of the end for Arsene Wenger at Arsenal, but it certainly accelerated the Gunners’ decline.