The club Ferguson served as a player in the late 1960s were in a state of disarray on the pitch barely 15 months ago, but Smith's arrival as successor to Paul Le Guen triggered a remarkable turnaround in fortunes.

Ferguson claims Smith has made "an unbelievable difference" since returning to the club in January 2007, even if he feels it will be difficult for Rangers to win the Clydesdale Bank Premier League due to their heavy workload between now and the end of the season.

Rangers have clinched the CIS Insurance Cup and remain hopeful of adding the UEFA Cup, Scottish Cup and SPL titles before the season is out. In the SPL they trail Celtic by five points, but have three games in hand.

Ferguson said: "A year ago they were about 15 points behind Celtic, there was a big reparations job to be done.

"It's not the best Rangers team in Walter's time by any measure but through organisation and team spirit - he has brought back that great Rangers thing of playing for the jersey - I think that he has made an unbelievable difference to the team.

"He has had a lot of injuries too but is in the position where he can win four trophies and that is quite amazing.

"I think he has a difficult task winning the league though because of the number of games they have got left."

Rangers must fit in six league games and the UEFA Cup final before facing Queen of the South in the Scottish Cup final on May 24.

Ferguson's own Manchester United side are looking ahead to a European final, a Champions League showdown with Chelsea in Moscow on May 21.

But he was thrilled to see Smith, who served as Ferguson's assistant with Scotland at the 1986 World Cup and briefly at United in the 2003-04 season, savour Rangers' UEFA Cup semi-final victory over Fiorentina.

A British winner could be crowned on home soil, with Rangers taking on Zenit St Petersburg at the City of Manchester Stadium on May 14.

Both veteran Scottish bosses could finish this season with European titles, and Govan-born Ferguson said: "I'm delighted for Walter, it's fantastic for him.

"My phone never stopped ringing last night, they think because the game is in Manchester that you have got all the tickets!

"It's fantastic for the club and they will bring about 50,000 fans down here."

Ferguson's United midfielder Darren Fletcher also hailed Rangers' achievement, despite his allegiance as a youngster belonging to the other side of the Old Firm.

Fletcher, 24, said: "Obviously I was a Celtic fan growing up but now I'm a fan of Scottish football.

"I was really pleased for Rangers last night, knowing Walter Smith as the former Scotland manager and knowing a lot of the players.

"Although I was a Celtic supporter growing up, you lose a little bit of it coming here - and your life revolves around Manchester United."

Motherwell manager Mark McGhee hailed the "fantastic" defensive qualities which earned Rangers another European shut-out.

In his playing days. McGhee helped Ferguson's Aberdeen beat Real Madrid in the 1983 European Cup Winners' Cup final after knocking out Bayern Munich along the way.

He knows what an effort is involved in taking a Scottish club to the final of a European tournament, and said: "You need to be a good team to do that and they have got past a lot of good teams, including Fiorentina.

"They nullified them brilliantly - now they have just got to go and win it."