The UEFA Champions League kicks off this week with powerhouses such as favourites Barcelona and holders Inter Milan yet to hit their stride, leaving the door open for nasty surprises in games they would ordinarily win.
Barca host Panathinaikos in their Group D opener on Tuesday after being stunned in a 2-0 home defeat by promoted Hercules in their second La Liga outing of the campaign on Saturday.
The Nou Camp will still be recovering from the shock with the fans hoping Lionel Messi and Spain World Cup winners David Villa and Andres Iniesta cannot play so badly again.
AC Milan, whose late signings of Zlatan Ibrahimovic and Robinho led excited fans to suddenly start snapping up Champions League season tickets, suffered similar woe at the weekend as they prepare to welcome Auxerre in Group G on Wednesday.
The seven-times champions lost 2-0 at promoted Cesena, a team with financial problems who are back in Serie A for the first time since 1991. Debutant Ibrahimovic missed a penalty.
Milan's new coach Massimiliano Allegri, a former Cagliari boss with no experience of European soccer, hopes the defeat would bring his millionaires down a peg or two after news Serie A players also plan a strike in a fortnight over contracts.
"It's a defeat which will do us good," he said. "We need to have a completely different attitude. You need sacrifice."
City rivals Inter fared only a little better, struggling to beat Udinese 2-1 with Diego Milito again looking a shadow of the striker who was key to their treble success last term.
New coach Rafael Benitez has looked extremely pensive in his first few outings in the Inter dugout, especially after an appeal for new players went unheard in the boardroom.
They start their defence with a Group A trip to Dutch champions Twente Enschede on Tuesday with doubts over the fitness of key defender Maicon and their entire formation given Benitez has just three established forwards to choose from.
SECURITY CONTROLS
Jose Mourinho, the architect of Inter's staggering success last season, starts his bid to become the first coach to win the European Cup with three different teams when his Real Madrid side welcome Ajax Amsterdam in group G on Wednesday.
Real too have looked lacklustre in their early season games although Cristiano Ronaldo returned from injury in Saturday's 1-0 win over Osasuna, where Real fans whistled the team at halftime, and should be firing on all cylinders by midweek.
Manchester United conceded two late goals to draw 3-3 at Everton on Saturday in a game Wayne Rooney was rested from given the abuse he gets from his former Everton fans and recent newspaper allegations about his private life.
The England striker looks set to return for Tuesday's group C opener at home to Rangers with police hoping confrontations stay on the Old Trafford pitch after laying down strict security controls on supporters of the Scottish champions.
On their last visit to Manchester for the 2008 UEFA Cup final against Zenit St Petersburg, rowdy Rangers fans rioted.
"That still does evoke some very painful memories for people in Greater Manchester and for genuine Rangers fans," Greater Manchester assistant chief constable Ian Hopkins said.
Chelsea are one top European side in excellent domestic form having won four out of four in the Premier League.
Carlo Ancelotti's side visit Slovakian champions Zilina for their Group F opener on Wednesday when last season's runners-up Bayern Munich host AS Roma in Group E.
