PAUL HARTLEY is a paid-up member of the Aiden McGeady appreciation society. Not only did the Scotland midfielder spend the formative years of his own career operating as a winger, he was also among the opposition back when McGeady made his full debut, scoring in a 1-1 draw against Hearts at Tynecastle in April 2004. So when he duly became the Republic of Ireland internationalist's club team-mate back in January, Hartley was well aware that McGeady was a good player. He just didn't know he was this good.

"The player that has stuck out for me recently would have to be Aiden because he has been terrific in the last six weeks," Hartley said. "He has gone and won games on his own for us, and I think the Benfica match showed what an outstanding player he can be.

"I knew he was good but I think this season you are seeing the best of him, because he is not just getting forward, he is having to track back and defend as well," Hartley added.

"He has been producing that for the last few weeks, and hopefully he will be a big player for us again in midweek. He has not just got ability, he can also get you 60-70 yards up the park, and take everyone up there with him. He is an exceptional talent, and I think he can go to the top, and do whatever he wants. He is a very hard trainer, always working on different things - whether it is in the gym or his shooting or his crossing. He has got real consistency now."

Celtic meet Shakhtar Donetsk this Wednesday in a crucial Champions League match, almost exactly three years since beating the same side 1-0 in the same competition at Parkhead.

Yet, somewhat remarkably, McGeady is the only member of either the starting XI or the substitutes from that evening still present at the Parkhead club.

With Gordon Strachan paying tribute this week to the painstaking hours the 21-year-old does in the gym working on his physical condition, it is quite literally a case of survival of the fittest.

"They have all got fitness programs but he McGeady seems to do more than anyone else," said the Celtic manager. "The ones that I see in the gym are the ones that seem to be doing well. They don't take their ability for granted.

"They have all got ability to be at this level, but it is about enhancing that ability. You can do that by practising with the ball, and physically making themselves better as well. For a young footballer there is no excuse for not using what we have here at Lennoxtown."

"He is still a young man,"

Strachan added about the man who proved the match-winner against Benfica last month, "but he has worked hard at his game, and the better you become physically the more confident you become. You don't get tired, so you don't make mistakes. Take the mistakes away, and confidence flows. Sometimes he used to try too hard and get down on himself if something miraculous didn't come off. His game has got simpler and better."

The stakes could hardly be much higher. By the time the final whistle sounds, Celtic fans would be best advised to have prepared themselves for every eventuality from qualification for the last 16 to outright Champions League elimination. A single-goal Celtic win, for instance, would complete another commendable clean sweep of home Champions League matches, and see Celtic go into the final game with nine points already to their name. Yet, with Milan in the San Siro as their last-day opponents, such an outcome could still be regarded as insufficient.

Having gone down 2-0 in Donetsk on the opening day, it is not inconceivable that Strachan may be presented with the unenviable dilemma late on in the match of whether to risk even a winning position in an attempt to overturn their current head-to-head disadvantage held by their Ukrainian opponents. Ironically, his predecessor Martin O'Neill was criticised for being overly defensive back in that same 2004 match, against a Shakhtar side who by the end had only nine men.

Then again Strachan knows all about the perils of trying to second guess the outcomes of football matches.

"When I was at Coventry, we stayed up on goal difference once, when Steve Lomas of Man City was keeping the ball in at the corner flag thinking it was enough to get a draw," Strachan said. "Lomas was keeping the ball in the corner thinking a draw was enough, but they got it wrong and went down. So, the first thing is to score more goals than the opposition, then where it goes after that I don't have a clue."

In any case, attempting to atone for that demoralising defeat in Donetsk should be motivation enough. The Parkhead side were two down in just eight minutes in Ukraine but back on home turf where they have been beaten just once in 24 Champions League outings (a record bettered only by Barcelona) they will hope to subject their opponents to a similar whirlwind.

"Their high tempo in the last match caught us," Strachan admitted. "I don't think we were expecting that, but it encouraged them that we gave them the first goal. We were in shock, similar to England in midweek. Sometimes you are able to ride it and keep it at 1-0, but, just like England, we weren't able to, and it went to two before it settled down."

Hartley's usual midfield role provides an insurance policy, but he also sees the advantage in going on the offensive. "We need a fast start to make sure they know they are in for a real test," he said.