While his instincts are clearly telling him to stick with the players and system that have served him so well over the past 15 months, Mick McCarthy still found himself faced with the prospect of making profound changes to his starting line up for tomorrow's play-off second leg at the Azadi stadium here in the Iranian capital.

Roy Keane, of course, is already gone and Steve Staunton and Niall Quinn continue to be sufficiently bothered by the injuries they picked up over the weekend that neither travelled from the team hotel to the stadium complex for the squad's first run-out since arriving on Monday night.

Both continue to look very doubtful for tomorrow's game although McCarthy insists that he will give them more time before making any final decisions. His deliberations were hardly helped during yesterday's session, however, by the fact that Gary Breen had to receive treatment after going over on his ankle for the second time in five days.

McCarthy insisted afterwards that Breen should be okay, and despite the Coventry player's poor display in the first game, the Ireland coach will hardly want to be forced into changing four of the six players through the centre of team.

The suggestion that he might go even further and alter the tactical approach was again raised yesterday when he was asked by journalists whether he might opt to bolster central midfield with an extra man while leaving just one striker up front. McCarthy, though, seems increasingly aware of his side's frailties when it comes to relying on a policy of containment and he insisted again that, "we've got to defend by attacking them.

"Everywhere we've gone we've scored goals: Holland - two, Portugal - one, Cyprus - four, Estonia - two, Andorra - three or whatever it was. We've been good against teams that want to attack, we're confident on the counter-attack and Iran are going to have to come out and attack in this game so there will be opportunities for us to score again."

Given Quinn's injury - team officials said he was still struggling badly - those opportunities look likely to fall to David Connolly and Robbie Keane, a partnership with a longish but fairly undistinguished history. The pair briefly played club football together at Wolves although an injury to Keane prevented them linking up for more than a handful for games.

McCarthy's preference for a bigger man to lead his attack has limited their time together at international level, although they started both the Cyprus and Andorra away games in this campaign. Connolly far outshone Keane in Nicosia but was taken off early the following week in Barcelona. Neither scored.

Connolly readily concedes that he has little hope of playing if Quinn makes it. "Mick has a preference for a big man and a little man. Robbie's front of the line for the little man's jersey and I'm, eh, not really in the hunt for the big one."

Though McCarthy would clearly like to stick with Quinn and mentioned after Saturday's game the importance of the big Dubliner's defensive capabilities against a big and fairly powerful Iranian side, the attractiveness of the younger Connolly may be enhanced somewhat by the fact that at 4,000 feet above sea level Tehran may pose particular physical challenges as a venue.

Connolly said that the difference had been noticeable from the start of yesterday's session, with the 24-year-old remarking "you could certainly tell that you were higher up, it took longer to get your breath back and the running was generally that bit harder although it wasn't too bad."

"The lads were blowing a bit when they were warming up all right," said McCarthy, "but after that it seemed okay. I suppose we really won't know how much difference it might make until the game gets under way."

McCarthy predicted that the altitude could definitely be expected to have some bearing on the two teams' tactical approach, with both probably looking to have a few long-range cracks at goal this time.

"The ball definitely flies a bit, there's no doubt about that and when we watched them here against the UAE they certainly liked to have a shot, they've got one or two that can hit it from distance.

"We'll encourage our lads to shoot too, of course, if the opportunity arises. It was difficult on Saturday, because there were so many players packed in there into the centre that there wasn't much space to be found, but I expect that it'll be slightly different this time around."

Local journalists, meanwhile, predict trouble here tomorrow evening if Iran lose out. "It is a somewhat different situation to the Bahrain game when 700 were arrested," said Ali Alavi of the local daily newspaper World Soccer, "because people firmly believed after seeing the way that their team played in that game that the result must have been fixed.

"If Iran loses this game there will certainly be trouble again, though, because football is all that Iranian people care about."