After a two-month hiatus, the UEFA Champions League returns this week with some mouth-watering Round-of-16 action, including a repeat of the 2006 final between Barcelona and Arsenal.
Three clubs go into the knockout phase boasting unbeaten records in this year’s competition: Barcelona and Manchester United, who both have four wins and two draws to their name, and Real Madrid, who have won five of their six matches played thus far.
Their respective coaches will be mindful that they are now entering a very different stage of the tournament though, as illustrated in last year's knockout phase. The two then-unbeaten sides fell by the wayside prematurely last season, Chelsea in the Round of 16 and Bordeaux at the quarter-final stage.
It is also worth noting that this is the fourth time that all four of England’s representatives have managed to successfully negotiate the group phase.
Finally, this year sees the Champions League maintain the change to the tournament schedule adopted last season, with only two matches being played per night. The remaining four first-leg games are scheduled for next week.
The fixturesFirst week Round of 16 matches, first legs (all kick-offs 20.45 CET)
Tuesday 15 February (return legs on 9 March)AC Milan - Tottenham
Valencia - Schalke

Wednesday 16 February (return legs on 8 March)Arsenal - Barcelona
Roma - Shakhtar Donetsk
Match of the day Arsenal-Barcelona, Emirates Stadium, LondonWhen the draw paired up these two sides, currently entertaining their fans with some of the most attractive football in Europe, there was little doubt that the clash would be given top billing. Josep Guardiola’s men require little in the way of introduction, and will once again look to their influential triumvirate of Lionel Messi, Andres Iniesta and Xavi to guide them into the next round. In five Champions League encounters, including the 2-1 defeat in the 2006 final, Arsenal have never got the better of the finely tuned Catalan machine, losing to them three times and drawing twice.
Last season, the Spaniards again put paid to the Gunners’ hopes in the tournament, registering a resounding Messi-inspired 4-1 victory at home, after the teams had shared a 2-2 first-leg draw at Emirates Stadium.
Arsenal appear better equipped than in previous seasons though, and boast players at the very top of their game, such as the dominant Cesc Fabregas and the free-scoring Robin van Persie, who has notched 11 goals since the turn of the year.
In terms of statistics, the match is just as intriguing, as the London side have been defeated just once at home in 33 Champions League games (3-1 versus Manchester United), while Barcelona have also only lost on one occasion in their last 15 outings at this level, when they succumbed 3-1 to Inter Milan in the 2010 semi-final.
The other matchesAC Milan – Tottenham: Knocked out on three occasions by English clubs over their last six European campaigns, AC Milan will be looking to ensure that Tottenham do not make it four in seven. Rossoneri coach Massimiliano Allegri will have to make do without the services of the injured Andrea Pirlo, as well as Antonio Cassano and Mark van Bommel, both of whom are cup-tied.
In order to win the all-important midfield battle, he will put his faith in the experienced hands of Gennaro Gattuso and Clarence Seedorf, and in the burgeoning talent of Alexander Merkel. Aside from breaking up opposition attacks, they will also be charged with providing telling passes for Robinho and the on-song Zlatan Ibrahimovic.
AC Milan’s backroom staff will be well aware of the threat posed by Tottenham, especially after having sized up their abilities at close hand during Spurs’ memorable 4-3 defeat to city rivals Inter in November. The side from north London trailed 4-0 that night, but came storming back, and away goals will now be key to Tottenham’s hopes of progressing. As befits the joint top scorers in the competition – they have found the net 18 times so far, equal with Arsenal – Harry Redknapp’s men will approach the clash with aspirations of piercing a hole in the Italian defence and thereby setting up a winnable second leg.
However, if AC Milan vice-president Adriano Galliani’s recent comments are anything to go by, defeat is simply not an option for his club: “For the last two years, we’ve been knocked out at this stage. It cannot happen a third time.”
Valencia-Schalke: Despite having featured in UEFA’s flagship club competition for five out of the last seven seasons, Valencia are not among the highly fancied candidates this time around. That will please coach Unai Emery, who would prefer his charges to continue flying under the radar. Emery’s task is to mastermind a home victory over Schalke, no easy task against a team that has conceded just three goals in the tournament so far, a record only bettered by two other sides.
Another considerable obstacle awaiting Los Che comes in the form of Schalke striker and Spain legend Raul, who scored a remarkable total of twelve league goals at the Mestalla while wearing the colours of Real Madrid.
Roma-Shakhtar Donetsk: Lacking in competitive action since the end of November due to the Ukrainian winter break, Shakhtar Donetsk have been training in Spain ahead of their tie with Roma at the Stadio Olimpico. This may be the first time in their history that Shakhtar have advanced this far, but given the team’s Brazilian flavour and the wily nature of Romanian coach Mircea Lucescu, who worked in Italy for eight years, it is highly unlikely that Giallorossi supremo Claudio Ranieri will approach the game lightly.
In order to engineer a way past the Ukrainian back line, the former Chelsea manager will rely on the goalscoring form of Marco Borriello, who has found the net in every one of Roma’s Champions League home matches so far, and the increasingly influential France international Jeremy Menez. The Rome-based side are short of first-choice defenders through injury and suspension, however, and will need to be wary of being caught out on the counter-attack.
Player to watchAC Milan’s high-profile match against Tottenham should provide Alexandre Pato with an excellent opportunity to demonstrate to a wider audience that the partnership he has developed with fellow striker Ibrahimovic has the potential to last. Despite hitting nine goals in 15 Serie A games so far this season, Pato has yet to fully live up to fans’ expectations since his arrival at the club in January of 2008. While he retains the all-important support of the coach, he will be acutely aware of the need to make an impression in his team’s upcoming matches, bearing in mind the fierce competition for places up front.
The stat
100 – in percentage terms, the number of times that Arsenal, Chelsea, Lyon and Real Madrid have qualified from the group phase since the introduction of knockout matches at the Round-of-16 stage for the 2003/04 season. They are the only four clubs to have achieved such a feat.
What they said“We finished top of our group ahead of Arsenal, achieving the goal we’d set ourselves. Anything after that is the stuff of dreams.” Shakhtar Donetsk defender Razvan Rat
Have your sayWill Arsenal finally gain some revenge on Barcelona for previous European defeats?