The return of the Champions League provides an exciting distraction from the domestic league battles across Europe. While Manchester United and Manchester City, eliminated in the group stage, watch on from the sidelines, the likes of Barcelona, Real Madrid, AC Milan and Bayern Munich re-enter the fray, chasing a spot in the last eight.

The road to the final in Munich on 19th May is still long and winding – but the history books suggest that Round of 16 ties are rarely short of drama. The favourites will be all too aware that if they do not hit top gear, upsets can easily occur.

Inside Futbol take a walk down memory lane, revisiting the top five Round of 16 ties since that format was introduced during the 2003/04 campaign:

FC Porto vs Manchester United, 2004

This tie will forever be remembered for then Porto boss Jose Mourinho’s frenzied celebrations as he raced down the touchline at Old Trafford after snatching a quarter-final place in the closing moments.

Mourinho’s men had claimed a slender lead in the first leg in Portugal, winning 2-1 courtesy a Benni McCarthy brace. A night that began so well for Manchester United, with Quinton Fortune’s opener, ended in dismay as Roy Keane was sent off late on.

Back in Manchester, United sgain seemed to have the upper hand through Paul Scholes’ goal, which put Sir Alex Ferguson’s men ahead on away goals. But disaster struck as United first had a goal wrongly disallowed for offside then conceded the equaliser that crushed their Champions League dreams.

Costinha was on hand to fire home after Tim Howard could only parry a McCarthy free-kick. And just like that, Mourinho was sprinting towards the corner flag and the upset had been sealed.

Werder Bremen vs Juventus, 2006

Werder Bremen goalkeeper Tim Wiese may still be haunted by memories of this tie. Though his blunder is the standout moment, there was an endless string of highlights throughout both legs.
A Juventus team boasting stars like Zlatan Ibrahimovic, Pavel Nedved, Gianluigi Buffon and Fabio Cannavaro were heavy favourites to cruise into the quarter-finals, but their German opponents earned a dramatic 3-2 victory on home soil in the first leg, with late goals from Tim Borowski and Johan Micoud.

Few doubted that Juventus would bounce back in the second leg, however the task grew considerably tougher when Micoud gave Bremen a surprise cushion inside the first 15 minutes. David Trezeguet levelled but, heading into the final minutes, Juventus still needed a winner to avoid elimination.

Then came the decisive error from Wiese, who had been otherwise excellent all night. The Bremen goalkeeper somehow dropped Nedved’s cross, providing Emerson with a simple tap in to spare Juventus’ blushes.

Arsenal vs AC Milan, 2008
Young legs and free-flowing passing came face-to-face with experienced heads and disciplined organisation in this tie. Paolo Maldini was still marshalling the Italians’ backline while Cesc Fabregas was emerging as Arsenal’s key man.

The first leg was a typical AC Milan performance away from home, arriving at the Emirates and riding their luck to clinch a 0-0 draw. Arsenal gave it their all but just lacked the finishing touch, leading many to write off their chances of progressing.

But the Gunners would not be denied. Arsenal took the game to AC Milan at the San Siro, kept Alexandre Pato and Kaka quiet and then delivered the knockout blow as first Fabregas drilled a low strike past Zeljko Kalac then Emmanuel Adebayor put the result beyond doubt, silencing the home crowd.

Arsene Wenger’s young charges had ruled the night in Milan, sending confidence coursing through this young squad. For the Italians, however, this was the end of an era as they bowed out of a competition they had dominated over the past five years.

Real Madrid vs Bayern Munich, 2007

There was no shortage of goalmouth action in this tie as some of the world’s top talents went toe-to-toe. The latest edition of the Galacticos were the favourites but Bayern were never likely to be fazed by their opponents’ firepower.

Real Madrid, determined to improve their disappointing recent Champions League record, seemed well-placed in the first leg, racing into a 3-1 lead thanks to Raul and Ruud van Nistelrooy. But Mark van Bommel’s late goal cut Real’s lead to a single goal and gave Bayern hope as they prepared to host the second leg.

Real made the worst possible start in Munich, with Roy Makaay scoring the fastest ever Champions League goal – after just ten seconds. Lucio doubled the lead in the second half and, though van Nistelrooy’s penalty set up a nervy finish, the Germans held on for a memorable victory. For Real, the result led to more questions and finger-pointing.

Chelsea vs Barcelona, 2005

It is hard to imagine another Round of 16 tie providing more excitement and drama than this classic, once again featuring Mourinho. Chelsea were on the rise under their new Portuguese manager while Barcelona were taking strides of their own, with an array of stars including Ronaldinho, Samuel Eto’o and Xavi.

In the first leg in Spain, Chelsea seemed on course for a dream night as a Juliano Belletti own goal presented the visitors with the lead. But a controversial red card for Didier Drogba turned the game in Barcelona’s favour as Maxi Lopez and Eto’o sealed a 2-1 comeback win.

Chelsea responded with a rampant start to the second leg at Stamford Bridge, scoring three times inside the opening 20 minutes. Cue 15 minutes of Ronaldinho magic as the Brazilian netted from the penalty spot then created space to poke a shot past Petr Cech from the edge of the box. Suddenly, Barcelona were back in the driver’s seat.

But there was time for one final twist as John Terry grabbed the tie-winning goal from a Damien Duff corner, sending Chelsea through to the last eight and beginning the rivarly between the two clubs. It was a night that no spectators would ever forget.