It is only in the last few weeks that Spurs' Premier League title challenge has faded following away defeats at Manchester City and Arsenal, plus a home draw with relegation-threatened Wolves.

Yet, they entertain Manchester United this weekend currently safe in third spot and with only a replay against League One Stevenage blocking the path to an FA Cup quarter-final against Bolton.

The key, according to Ferguson, was the positive message Tottenham sent out in keeping Modric.

A one-time target of United, the Croatian seemed destined for Chelsea and pleaded to join the Stamford Bridge outfit.

Spurs chairman Daniel Levy said no, and then manager Harry Redknapp cajoled Modric into a series of outstanding performances upon which Tottenham's quest for honours has been built.

"The fact they decided to hold on to Modric against what everyone thought was a big Chelsea bid swung the players around," said Ferguson.

"That was an indication that they mean business and it has worked because they have had a great season.

"Up until three weeks ago they were playing the best football in the league."

Tottenham's present hiccup seems certain to ensure they do not end their long wait for a championship.

It does not make them any easier to beat though.

Having kept the gap to leaders Manchester City to a couple of points thanks to Ryan Giggs' last-gasp winner at Norwich, Ferguson views this weekend's encounter at White Hart Lane as a pivotal encounter in the season.

United certainly have a run of fixtures after Tottenham which should bring maximum points and allow them to exert maximum pressure on City.

So a 25-match unbeaten record against Spurs bodes well.

Ferguson is wary though, particularly as this Tottenham side, despite throwing away a two-goal lead at Arsenal on Sunday, look far stronger than most.

"He (Harry Redknapp) has added a lot of exciting players," said Ferguson.

"He has changed them right round in the last few years.

"(Kyle) Walker has been a tremendous full-back for them this season. He has great pace going forward. And they have pace from the other side from (Gareth) Bale.

"They have really clever players and everyone recognises what a terrific player Modric is.

"Overall, they have had a great season.

"They have hit a plateau but we know Sunday is an important game for us. The most important game so far."