Flaws of Champions League 'big three' could see surprise winner emerge in May
A cloud of uncertainty has descended over the Champions League this season and it may throw up a surprise winner when the final is played out in Cardiff next May.
Not since Jose Mourinho's FC Porto lifted the crown in 2004 have we had a surprise winner but all that could change this season.
Manchester United and Liverpool are among the big-name absentees from Europe's elite competition and the superpowers that are battling it out all appear to be showing signs of fragility.
Ahead of an intriguing set of matches this week, here is your Sunday World guide to a competition that is more likely than ever to throw up a surprise finalist.
IN THEIR FAVOUR: Lionel Messi, Neymar and Luis Suarez
QUESTION MARKS: Defensive woes coming to the fore for the Nou Camp masters
The extraordinary standards we expect to see from Barcelona means their start to this season has been disappointing.
Their 4-3 La Liga defeat against Celta Vigo earlier this month cemented a suspicion that Luis Enrique's team have fallen from the pedestal they were on when they last won the competition in 2015.
An injury to veteran midfielder Andres Iniesta has not helped the mood of concern hovering over the Nou Camp, with their defensive flaws becoming all the more apparent in a season when Messi has struggled with injury niggles.
Their Champions League thrashings of Celtic and Manchester City confirm that even a misfiring Barca can tear opponents apart, yet there are enough weak spots being exposed to give their rivals hope.
VERDICT: Barcelona are not in the kind of consistent form to strike fear into their rivals right now.
THE LIKELY LADS
IN THEIR FAVOUR: Champions League winning coach Carlo Ancelotti
QUESTION MARKS: Uncertain form has undermined confidence
Germany's superclub hired a Champions League icon when they replaced departing manager Pep Guardiola with three-time winner Ancelotti but the Italian maestro inherited a team that is in something of a transitional phase.
They may be riding high at the top of the Bundesliga once again but the old guard of Arjen Robben and Franck Ribery are reaching the end of their glorious careers, and new faces are now emerging to replace them.
They have looked vulnerable defensively on occasions, with a defeat against Atletico Madrid in the Champions League and draws against Koln and Eintracht Frankfurt in the Bundesliga suggesting their new boss will need time to find a winning formula.
VERDICT: Bayern have a wonderfully talented squad, but they are seeking to find a fresh identity under new boss Ancelotti.
IN THEIR FAVOUR: This club has a Champions League winning mentality
QUESTION MARKS: What has happened to Cristiano Ronaldo?
Real Madrid President Florentino Perez will soon be forced to consider whether Zinedine Zidane is ready to be the long-term coach of the reigning European champions.
Zidane took the plaudits flowing his way after last season's Champions League final win against Atletico Madrid, yet his side's unconvincing form in recent weeks has raised doubts over the credibility of this novice coach to remain in the job for the long-term.
Zidane's relationship with talisman Cristiano Ronaldo has been the subject of much scrutiny following his decision to substitute the Portuguese superstar in a game against Las Palmas last month, and his tactical acumen is set to be examined further in the months ahead.
Ronaldo had looked off the pace and low on confidence after returning from the injury he picked up in the Euro 2016 final and jeers from the Bernabeu crowd last weekend cast doubt over the forward's invincibility. However, a hat-trick on Saturday might just be the turning point in the former United man's season.
VERDICT: Real Madrid rode their luck to win the Champions League last season but they do not look ready to repeat that trick this time.
THE ENGLISH CLAN
MANCHESTER CITY, TOTTENHAM HOTSPUR, LEICESTER CITY, ARSENAL
IN THEIR FAVOUR: The unconvincing form of the 'big three'
QUESTION MARKS: So many for all four to answer
No English team has made it through to a Champions League final since Chelsea lifted the trophy back in 2012 and it's hard to see any of this season's quartet ending that miserable run this season.
On current form, Arsenal may be the side with the most realistic chance of extending their run in the competition into the semi-finals and beyond.
However, Arsene Wenger's men prove year after year that they are no match for the best sides in Europe when the pressure is applied and the same story is likely to transpire this season.
Leicester's march through a weak group is all but assured after three wins so far but Claudio Ranieri's men are unlikely to extend their run much beyond the last 16 unless they can land another fortunate draw.
Meanwhile, Man City do not look ready to challenge for Europe's top prize in Pep Guardiola's first season at the helm.
VERDICT: If Tottenham find their feet in their temporary Wembley home, they could go deep in the competition. Winning it will be beyond them.
THE DARK HORSES
ATLETICO MADRID, JUVENTUS
After coming close to lifting the Champions League trophy on two occasions in the last three years, Diego Simeone's Atletico Madrid may be due a break or two in the competition.
Dogged, indefatigable and so tough to break down, Atletico have the resilience to dilute domestic rivals such as Real Madrid and Barcelona, while they have already recorded a morale-boosting win against Bayern Munich in this season's Champions League.
Meanwhile, Juventus have been stuttering in their defence of the Serie A title, inspiring coach Massimiliano Allegri to offer these words of confidence in his under-pressure side.
"It doesn't worry me that people say Juventus are winning without playing well," says Allegri.
"I don't know what 'playing well' means. The result is what matters. People remember who wins titles, not who plays 'well'.
"Judge us at the end of this season, not now."
VERDICT: Atletico Madrid are equipped to make it through to another Champions League final and, just maybe, this will be their season.
WATCH OUT FOR:
SEVILLA, BORUSSIA DORTMUND
IN THEIR FAVOUR: Proven pedigree in European competition
QUESTION MARKS: Injuries and dips in form are a serious concern
An unprecedented hat-trick of Europa League wins over the past three seasons confirmed Sevilla's status as a team that can challenge for major prizes.
Now they have started their Champions League push in encouraging fashion, with their draw against Juventus in Turin backed up by wins against Lyon and Dinamo Zagreb.
The departure of Europa League winning master tactician Unai Emery to Paris Saint- Germain was a blow last summer, but his replacement Jorge Sampaoli is finding his feet at Sevilla after an tricky start.
Thomas Tuchel is also a coach to be reckoned with as he has steered the Borussia Dortmund ship with impressive efficiency since Jurgen Klopp's departure in the summer of 2015.
Dortmund are a serious threat if all their star names are fit and firing but injury worries affecting star men Marco Reus, Pierre-Emerick Aubameyang and Andre Schurrle have contributed to shaky form in the German Bundesliga.
VERDICT: If these two hit form at the right time, they could challenge Europe's big hitters.