With the league series squared after three matches, tomorrow's Old Firm Scottish Cup semi-final at Celtic Park has an uncertainty not felt for several years.

For most of the last decade Rangers have been clear favourites but Celtic's resurgence under Wim Jansen, and home advantage tomorrow, have swung the odds marginally their way, even if they have faltered in recent games.

Since losing to Celtic in January the defending champions have looked pedestrian, although they have taken encouragement from their latest results, three successive league wins. The return to scoring form of Ally McCoist and the improved performances of Jonas Thern in midfield - the Swede has scored three times in as many games have cooled the fever that afflicted supporters over the sale of Paul Gascoigne to Middlesbrough.

Ibrox manager Walter Smith believes the fact that his players have been around the block before could be all-important in the final few weeks of the season. "We have shown throughout the years we can handle pressure."

Smith has doubts over his goalkeeper Andy Goram and central defender Sergio Porrini, and seems likely to revert to a central three in defence.

Celtic, who have dropped four points in three games, will be without their injured left-back Stephane Mahe and suspended midfielder Morten Wieghorst and there is a serious doubt about Jackie McNamara.

The opposition in the final should be known in advance, as Hearts and Falkirk meet at Ibrox today. The First Division side, last year's beaten finalists who are trying to stave off bankruptcy, are without the 6ft 7in defender Kevin James; Hearts should be close to full strength.