Injuries, fluctuations in form and changes in the dugout all have the potential to change the picture for teams competing in the knockout rounds
Getty16Lyon
With a fully fit squad, Lyon would have fancied their chances of at least troubling Juventus in their last-16 tie. After all, the French outfit have once again assembled a panel of young, talented footballers.
Moussa Dembele is expected to move to the Premier League sooner rather than later, Houssem Aouar and Lucas Tousart are two tremendously talented midfielders, while the 16-year-old Rayan Cherki looks like a superstar in the making.
However, Lyon are currently languishing in 11th place in Ligue 1 for a reason: season-ending injuries to Dutch forward Memphis Depay, their best player, and midfielder Jeff Reine-Adelaide.
The January signing of Bruno Guimaraes has lifted spirits around the Groupama Stadium but without Depay, it's virtually inconceivable that Lyon could become only the second French team to win the Champions League.
AdvertisementGetty Images15Valencia
It's been a topsy-turvy campaign for Valencia, who surprisingly sacked Marcelino just before their Champions League opener against Chelsea last September.
Amid the all-too-familiar climate of chaos at Mestalla, successor Albert Celades led Los Che to victory at Stamford Bridge and, ultimately, into the knockout stage after another fine win on the road on matchday six, this time at Ajax.
So, this is a team capable of upsetting better teams, as they've since hammered home by recently taking four points off Real Madrid and Barcelona in La Liga.
Captain Dani Parejo continues to lead by example in midfield, Ferrar Torres is developing rapidly into a fine winger, while Maxi Gomez is in decent form up front.
However, Valencia's seventh-placed ranking in La Liga represents an accurate reflection of their current strength. On the face of it, Atalanta are a good draw for Celades' side but one fears for the most porous defence in the top half of the Primera Division table against Papu Gomez & Co.
Getty Images14Napoli
Nothing can be taken for granted when it comes to Napoli.
This is a side that can lose at home to Serie A strugglers Lecce and then beat leaders Inter in the Coppa Italia four days later, so it's difficult to know what to expect from the Partenopei in the last 16.
Barcelona represent a rotten draw for a team that really should have topped their group, after taking four points off Liverpool, but Napoli were in utter disarray at the time because of a dispute between chairman Aurelio de Laurentiis and Carlo Ancelotti's players.
Rino Gattuso has restored some order but all is still not right at the San Paolo.
Still, the former home of Diego Maradona will be packed to the rafters for the visit of the Argentine's heir, Lionel Messi, and Napoli are undoubtedly one of those sides that rise to the occasion.
Getty Images13Chelsea
Frank Lampard remains on course for a successful first season as Chelsea boss. The Blues are fourth in the Premier League and looking forward to a mouth-watering Champions League last-16 tie with Bayern Munich, the side they defeated on penalties to famously lift the trophy in 2012.
However, that is not to say that all is rosy at Stamford Bridge. Having been unable to sign any new players when he returned to west London last summer, Lampard understandably expected new signings in January after Chelsea's transfer ban had been halved on appeal.
The legendary Blues midfielder was, thus, bitterly disappointed by the lack of incoming transfers, not least because it became clear during the first half of the season that his young and patchy squad needed an adequate understudy for Tammy Abraham and a dominant centre-half.
In fairness, Chelsea have subsequently announced that Hakim Ziyech will arrive in the summer to belatedly fill the creative void left by Eden Hazard's departure for Real Madrid last summer, but the fact remains that Lampard's side struggle to break sides down, while the defence looks ill-equipped to deal with the likes of Robert Lewandowski.