Defender Steven Whittaker believes keeping a clean sheet at Ibrox against Sporting Lisbon is the key to Rangers' UEFA Cup hopes.The Gers face the Portuguese side in the first leg of their quarter-final on Thursday night after shutting out Panathinaikos and Werder Bremen in Glasgow.

Those defensive successes helped Rangers progress after the away legs and Whittaker is sure another will put them in the driving seat.

"The home legs at Ibrox, we have done well not conceding any goals and when we go abroad we are capable of scoring goals on the break," said the former Hibernian full-back.

"Hopefully we can keep a clean sheet again. Away goals in European competitions are vital."

The progress of Walter Smith's men to the last eight, past a club who were sitting second in the Bundesliga, has given Rangers fans confidence ahead of a game against a side having an indifferent season in the Portuguese league.

But Whittaker knows only repeating the hard work shown in the earlier rounds will see them through again.

"We have exceeded expectations a little bit but that's credit to the boys," the 23-year-old told Rangers World.

"We have worked so hard, we have come under the cosh against quality opposition but dug in there and are still in the competition."

The game sees Rangers compete in the last eight of a European competition for the first time in 15 years.

That achievement comes with Smith well-placed to claim a domestic treble following the club's barren seasons under Alex McLeish and Paul Le Guen.

But one member of the only Rangers team to lift a European trophy, former sweeper Dave Smith, believes his namesake will have to spend in the summer to add flair to their winning ways.

Smith, who helped Rangers knock out Sporting Lisbon during their successful European Cup Winners' Cup campaign in 1972, said: "Results are impressive, but the way they play? Not really.

"With my style of play, I wouldn't be impressed, they can't pass the ball. I don't see Walter is that impressed.

"But Rangers need to win, you use what you have available to win. They have got to play to their strengths.

"A manager never asks a player to do what they can't do. Le Guen was asking players to do what they couldn't do - pass the ball.

"If you think back 10 years, nobody will remember how Rangers got through.

"He has got to make signings to improve. You can't make players into silky players if they are not silky.

"As Gordon Strachan is finding out, the only thing that matters to the Old Firm is to win."

Smith helped Rangers reach the quarter-finals despite losing a penalty shootout in Lisbon after the referee had overlooked the new away-goals rule.

But it took a revenge semi-final win over Bayern Munich to convince Smith, who now runs the Salutation Inn in Montrose, that his side's name was on the trophy.

"The game we started to believe was when we beat Bayern Munich because they beat us in 1967," Smith told said.

"For four of us, it was possibly the last chance to win a European trophy.

"John Greig, Willie Johnston, Sandy Jardine and myself were the only four that had played in that final.

"We had lost the first one and we weren't going to lose the second."

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