Paul Gilham/Getty Images
Jan Vertonghen is a fine defender who could do with taking on more responsibility for his team.
Part of Tottenham's trouble is that they do not have a system for all occasions. The defense is so focused on keeping their shape higher up the pitch, it is sometimes at the expense of their primary responsibilities around the penalty box.
The 2-2 home draw with Basel was the most startling recent example of this.
Winger Mohamed Salah consistently had Spurs on the back foot, his forward-driving runs leading his team's attack. Frequently having to turn round and face their own goal—Benoit Assou-Ekotto, Jan Vertonghen, William Gallas and Kyle Naughton were disorganized and unprepared by the time they reached their penalty box.
Good teams can do that to you, and sometimes the priority has to be defending from the back.
More than anything though, Villas-Boas' attempts to fashion a new defensive mindset at Spurs have been undermined by issues with personnel (sometimes of his own doing, eg. the frequent rotation) and, chiefly, the failure of several defenders to assume acceptable standards of responsibility in their jobs.
During the opening third of the season, the three most senior defenders used—Gallas, Vertonghen and Kyle Walker—were often woeful in marking and tracking opposition players. As the most experienced, Gallas' lack of leadership was especially culpable for the back four's rudderless nature.
On paper, the defenders Villas-Boas was playing were more suitable for a higher line. This notion was thoroughly ripped to shreds by their embarrassing failure to perform even the most basic of defensive duties against Arsenal in November—a turning point that saw the long overdue re-introduction of Michael Dawson to the starting lineup.
Dawson knows how to properly defend (blocking, tackling, heading) in the vital area in front of his own team's goal. Crucially, he also knows how to organize others around him and make sure they are doing their jobs too. Spurs have largely benefited from that since then.
The captain is not perfect. His lack of pace has seen him caught out at times since then, and in the end, it will likely see him replaced. But as of right now, no other Spurs player is capable of leading the defense.
Playing a high line and everything it encompasses—deciding when to move, understanding between defenders—is so reliant on good leadership. For Spurs to make it work in the long run, the onus cannot be on just one man to lead the way.
Vertonghen's development in this regard will be intriguing having had a full year behind him in the Premier League come next season. Walker has certainly stepped up his efforts following the costly error he made in the defeat to Liverpool. There is also a lot of hope Steven Caulker will progress into one of Tottenham's best all-round defenders.