With the European showdown looming on Wednesday, Smith's players could be forgiven for allowing themselves to look ahead to an occasion they may never experience again in their careers.

But the Rangers manager insists too much is at stake against United to even contemplate the clash with Zenit St Petersburg at the City of Manchester Stadium next week.

A win against United would slash Celtic's lead at the summit of the SPL to a single point ahead of the champions' own crunch match with Hibernian on Sunday.

Rangers would then have a game in hand still to play.

Both halves of the Old Firm are keenly aware there is no further room for error as the title race heads towards a much-anticipated conclusion - even if that does mean putting the UEFA Cup on the back-burner for now.

Smith said: "The importance of the league championship is a big thing for anyone and I think, this season, we have been focused enough.

"I don't think we need any warnings about not focusing on tomorrow's game - everybody knows exactly what it means.

"We saw the other night [against Motherwell] from the crowd reaction alone just how much they want to get behind the team and want them to win. So I don't think it will be a factor tomorrow."

Smith says his team selection for the visit of Craig Levein's men will not be influenced by the UEFA Cup Final.

The Scottish Premier League refused to sanction the postponement of the match ahead of the trip to Manchester and, as far as the Ibrox boss is concerned, it is business as usual this weekend.

"Some of our players have had a little bit of a strain placed on them with the number of matches they have had to play, but that's just the way it is," said Smith.

"The boys want to play. They have shown, physically, they are handling it and I think they are getting there mentally now as well.

"They can start to see the beginning of the end of the games and they are looking forward to every one of them.

"We are in good shape despite tomorrow's game being the fourth in nine days, and we are looking forward to the remaining fixtures as well."

Rangers have the opportunity to put points on the board and increase the pressure on Celtic ahead of their own match 24 hours later.

But Smith insisted: "This aspect of catch-up, or an imbalance in fixtures, is just something that's there.

"We have to win the games. We know after drawing at Easter Road that's our situation and that's the pressure we are playing under at the moment.

"It's a far better one than last year when we went into the last couple of games with nothing to play for."

Dundee United have been one of Rangers' most difficult opponents this season, claiming four points from their meetings at Tannadice, as well as losing out in the CIS Insurance Cup Final only after extra-time and penalties.

And, with a UEFA Cup slot up for grabs, Smith expects the Tayside outfit to go for the jugular again at Ibrox.

"They've been doing it all season," he said. "They have been aggressive in their approach to the games and by that I mean they like to get forward.

"They've enjoyed a good season and they can turn it into an exceptionally good one by gaining a UEFA Cup place so they will be up for the game.

"They will be ready for this one and I would fully expect a really good game."