LONDON: The champions of Spain against the champions of Italy. The most successful side in Spanish history against the most successful side in Italian history. A repeat of last season’s final (and the final of 1998). Real Madrid’s trip to Turin to face Juventus today is a clash of undoubted pedigree, and yet doubts swirl around both sides. For Juventus, there are familiar questions about the quality of Serie A. Napoli put up more of a fight than many anticipated, but Juve’s lead is now four points and they should wrap up a seventh straight title (and given they’re in the final of the Coppa Italia, quite possibly a fourth straight double.) And yet against Tottenham in the last round, there were long spells when Massimiliano Allegri’s side were dominated, apparently unable to deal with the pace and power of the team that lies fourth in the Premier League. They were streetwise and ruthless enough in front of goal to take advantage of Spurs’ naivety but the overall picture was concerning. Perhaps that is a natural result of the way football’s economy funnels capital to a handful of clubs in a handful of leagues, Juve’s domination at home meaning they are only partially equipped for the challenges they face in Europe. Similar financial fundamentals underlie the issues at Real Madrid. There is, on the face of it, something vaguely absurd about the fact that Zinedine Zidane’s position at Madrid is under threat. He could this season become the first manager to win the Champions League three times in a row, having last season become the first since Arrigo Sacchi in 1990 successfully to defend it. With Madrid 13 points adrift of Barcelona in the league, though, the sense is that if Zidane does not win the Champions League he will be gone. It is a situation that sums up the absurdity of super-club economics, suggesting on the one hand the impatience of owners, fans and media, the demand that success should be constant, and on the other the way that clubs of a certain stature can take a certain level of progress for granted. For Real, being in the quarterfinal of the Champions League is no great achievement. There lingers a feeling that Zidane, despite his success, is not a great coach, that he has collected silverware by dint of having at his disposal of squad packed full of great players. It is true their 2016 Champions League victory came thanks to an extremely fortuitous draw, but last season they had to beat Napoli, Bayern Munich, Atletico and Juve. It was striking during that run how often Zidane made substitutions that changed the game. At the same time, though, Zidane’s sides rarely control games. Again and again they concede soft goals and are forced to come back. They frequently have the quality to do that, and have tended to be rather more efficient in Europe, but it is a persistent niggle. They too had their problems against Tottenham this season, drawing in their home group game before being comprehensively beaten at Wembley. That said, Zidane’s use of a 4-4-2 in the last round against Paris St. Germain, leaving out Luka Modric and Toni Kroos, suggested a tactical audaciousness, and his substitutions helped turn the first leg just as surely as Allegri’s turned Juve’s second leg against Tottenham. Still, though, it feels like his future depends on this competition.