PART of the success of the Champions League knockout phase as a TV spectacle rests in shaking neutrals from the mid-season torpor that comes from realising the team you support likely won’t win the title or face relegation and you can only muster so much excitement from achieving mid-table respectability or – especially if you are an Arsenal fan -– yet another top-four trophy.

Instead, we effectively hit the reset button to get a brand, spanking new knockout competition, stocked with the game’s biggest stars, the ones we see in highlight clips and play with on Fifa.

And the first batch of games, coming up this week, offer a generous dose of potential upsets.

Start with the box office, Paris St Germain and Barcelona. Despite winning eight of nine domestic trophies under Laurent Blanc, PSG dumped him with little ceremony in the summer, finding his folksy, simple ways decidedly underwhelming. They wanted a visionary, a tactical savant and figured that with Zlatan Ibrahimovic departing (let’s face it, with the big Swede in your line-up you are not going to get too tactically cute, it’s easier and more logical to simply lump it up to him) there was no time like the present.

So they opted for Unai Emery, who had overachieved at Sevilla, delivering three consecutive Europa League titles. Except it has been a bumpy ride, with Emery struggling to impart his wisdom to a group of (largely) jaded veterans used to Blanc’s more meat-and-potatoes approach.

The fact the new signings – from Grzegorz Krychowiak to Jese to Hatem Ben Arfa – have contributed little hasn’t helped. The good news is that PSG are now rolling again – winning 10 of 11 in all competitions – and Edinson Cavani is doing his best Ibrahimovic impression. His two goals on Friday took his seasonal total up to 33 and while he may always be an acquired taste to some, it’s enough to give the Parisians hope.

Particularly since Barcelona, like PSG, have stuttered this season. Luis Enrique’s decision to use the full extent of his squad to keep the big guns fresh has meant they have dropped points in La Liga while producing some hum-drum performances. On top of that, Andres Iniesta and Sergio Busquets are only just now returning from injury.

Having Lionel Messi, Luis Suarez and Neymar up front can, of course, paper over a lot of cracks. But there is a fragility at the Camp Nou this season that we haven’t observed in some years. And Luis Enrique – despite winning a Treble in his first season and a Double in his second – is being questioned, with plenty willing to dip into the schadenfreude if his grand squad rotation plan results in counting chickens before they hatch.

Arsenal’s draw with Bayern Munich was greeted with the usual caustic comments about yet another Round of 16 exit against a European power. Right now, the doom-and-gloom brigade appear vindicated given the horrid run of form which has put even the perennial top-four finish in doubt. Throw in the perennial uncertainty over Arsene Wenger’s future – this time receiving an extra boost from Ian Wright on Friday night – and you can see why morale is low.

Yet things aren’t overly rosy in Bavaria either. After three years drilled in the ways of Pep Guardiola, the transition to Carlo Ancelotti hasn’t been smooth. Bayern were still top of the table – with a four-point lead over Leipzig – heading into the weekend, but it has been a turbulent week, following the announcement by Phillip Lahm that he would be retiring at the end of the season, and a club statement that suggested the timing was a surprise to them.

Ancelotti has said in some ways it is tougher to take over a successful side because you need to figure out what to change and to what degree to change it. He knows he can’t simply ape Guardiola so he needs to build on his predecessor while conforming to his view of football. That has meant pressing intermittently and being more direct in the final third. It is a formula which his players have only absorbed in part and matters have been exacerbated by the mysterious loss of form of club icon Thomas Mueller; this time last year he had 14 goals, now he has one. Which suggests that scaling this Bavarian mountain may not be as prohibitive as it appears for the Gunners.

Napoli must feel the same way about their encounter with Real Madrid. They haven’t lost since October and have won 11 of their last 13 in all competitions. Their manager, Maurizio Sarri – a guy who never played professionally, worked in a bank and coached amateur sides until his mid-40s – is the toast of Serie A right now and in Dries Mertens, a diminutive winger converted to centre-forward who has notched 20 goals already this season, boasts one of the hottest players in Europe. There is an excitement in the shadow of Mount Vesuvius not seen since the days of another prolific pint-sized virtuoso and, at the risk of blasphemy (and with a light heart) some local media have taken to calling him Diego Armando Mertens.

Real Madrid have the lead and games in hand in La Liga, but they have been knocked out of the Spanish Cup and hit hard by injuries. Luka Modric, Marcelo and Dani Carvajal are all returning from injury and while they may be fit for Napoli’s visit, they are unlikely to be match fit. Gareth Bale won’t be fit at all, at least not for the first leg. For a team who have gone 40 games unbeaten only to lose twice in the past month, the possible drop in form comes at the wrong time.

Finally, there is Benfica who could be forgiven for thinking about an upset of their own against Borussia Dortmund. After all, they reached the quarter-finals last season and hung on to many of their stars.

Thomas Tuchel’s men on the other hand are in full rebuilding mode. The decision to go with youth to replace the likes of Mats Hummels, Ilkay Gundogan and Henrikh Mkhitaryan may pay dividends in the long run, but short-term it has resulted in an inconsistent team, made even more so by Tuchel’s penchant for perpetual squad rotation and high-risk football.

Don’t be surprised if these four ties are a lot closer than they appear. Or even if a couple of the so-called big clubs emerge with a bloody nose.