As a player who brought incredible success to Tottenham Hotspur, including two FA Cups and a UEFA Cup victory in 1984, Osvaldo 'Ossie' Ardiles knows a lot about quality.
A World Cup winner with Argentina in 1978, the diminutive midfielder was signed by the White Hart Lane club in a transfer coup the following summer, and along with fellow countryman Ricky Villa went on to become a Tottenham legend. Not even an ill-fated managerial spell in 1993 could diminish his standing amongst Spurs fans.
Speaking exclusively to ESPNsoccernet about his former club's current plight at the wrong end of the table as they prepare to face Arsenal in one of the most eagerly anticipated derby games in recent memory, the Argentine was hopeful that the game could mark another turning point in their season.
''The last derby game [a 4-4 draw at the Emirates when Spurs scored twice in the final minutes] was an incredible turning point for Tottenham, and for Arsenal as well,'' he says. ''This is why derby games are so important. I believe it is a good time to play Arsenal.
''It is going to be a tight game and Arsenal are not playing as well as they could be. They have not been as consistent as in previous years and there are teams like Manchester United who are playing much better than them.
''But Tottenham are having problems as well and Harry [Redknapp] is a going to be a little frustrated because he knows how much quality Tottenham have.''
With Tottenham currently sitting in 14th place, hovering just a point about the relegation zone after enjoying success in the Carling Cup last season, the club have struggled to realise their potential and Ardiles points to the departures they have suffered in recent times as the main reason for their decline.
''You have to go back a little bit, as the Carling Cup success was supposed to be the springboard for this season,'' he says.
''But after that, the side started to deteriorate and they only won a few games at the end of last year. At the start of this season it looked as if there were a lot of problems with the club. Defoe had left, and then Robbie Keane went to Liverpool; but the one that caused the most problems was Dimitar Berbatov going to United.
''When the season started, there were a lot of new faces at the club and they endured a very bad start. With only two points after eight or nine games, they started to look at their situation and worry. I went to see them and they looked very, very bad.
''But then [after Juande Ramos' sacking] they started to put some results together and turned things around. There was a new aura of optimism and confidence in the place.
''That was fine for a while, but lately they have run into a few problems again and have not been getting the results they should be getting.''
As Tottenham manager, Ardiles had spent money on improving his squad with the likes of Jürgen Klinsmann, Ilie Dumitrescu and Gheorghe Popescu in the 1994 close season, but was sacked in October 1994 with the club battling relegation and knows from personal experience that signings do not always make the difference.
However, the Argentine believes that after spending a small fortune on bringing some of the old players back to the club, including a £15m outlay on Keane, Tottenham will start to turn things around.
''Robbie was very loved before he left Tottenham,'' he says. ''He played with a lot of passion and he relished coming back to the club after his bad spell with Liverpool. The defence was not good, but the main problem was the lack of power up front. So with the signing of Jermain Defoe, the signing of Keane, I expect things to dramatically improve in that respect.''
Keane should make his second debut for Spurs in the weekend's derby at White Hart Lane and, in the absence of the injured Defoe, Ardiles believes Tottenham's season can be kickstarted with a win.
''It is not only the result, but winning a derby means so much more,'' he says. ''Winning against Arsenal gives you so much confidence and it somehow translates into what is going to happen in the rest of the season. I always enjoyed playing in these games.''
With the club embroiled in a relegation battle, this weekend's fixture in North London has an added importance, but Ardiles does not believe that his former club are in danger of dropping into the Championship.
''Tottenham have too much quality to go down,'' he says. ''It is a dangerous word, but they have much better quality than the other teams around them involved in the relegation battle.
''They should not be in the position they are in at the moment, but the main frustration for Harry is that he has seen how well the side can play.
''Against Stoke they were excellent, but then against Burnley they were awful. That will be baffling for the manager, but they have every chance of turning it around against Arsenal.''
Relive the best North London derbies of all time this weekend from 10:40am, Exclusively NOT Live on ESPN Classic (Sky Channel 442). For details visit: www.espnclassic.com