HEAT may well be the toughest opponent Rangers have to take on in the notorious Toumba Stadium tonight but, according to the PAOK manager, they have problems of their own, namely Rod Wallace.

The temperature in this smoky industrial town - it is the biggest producer of cigarettes in the country - if the week's sultry weather continues, will be in the nineties at kick-off time.

Although the manager, Dick Advocaat, has been as thorough as you would expect of such an experienced European coach, going into minute detail to have his players prepared physically as well as mentally, the attitude of German referee Markus Merk could have a vital bearing on the night's events.

Ideally, Advocaat would like to see plenty of drink available around the park, as was the case when he was Dutch coach during the World Cup in America, but he is certain Merk will not allow that.

''I know the referee and he is a very strict man.'' And although he did not say so, the implication was there also that PAOK, who are more used to the conditions, would object to a slight bending of the rules however sensible it may appear.

However the coach is not too worried about the prospect of such a hot setting, and that's not counting the local fans. ''It is essential, of course, to get as much liquid down before the game as possible, from today on.''

That is why he has instructed his players to drink, drink and drink again before they start the defence of their 2-0 lead from the opening leg of this UEFA Cup qualifying tie.

Such an instruction might have been interpreted in a different way not so long ago by at least one individual who has departed the scene, but Advocaat knows he did not need to add the amendment ''and I mean water.''

A team doctor said that the players would be filled with water and calorie-enriched drinks.

''The idea is that they will be fully hydrated by the kick-off because it is possible to lose as much as a stone in the 90 minutes.''

Meantime, Oleg Blokhin, the Russian in charge of PAOK, was none too pleased with his team's showing against Ionikis in Athens at the weekend. The team in which former Dundee United man Craig Brewster is something of a hero beat the Thessaloniki side 1-0. ''I wanted to go into the second leg against Rangers with a positive result behind us,'' he said.

Asked about Rangers, he replied: ''The player that concerns me most is Wallace. If we give him space, he will punish us and it has to be said that our defence has not been playing well.''

It is remarkable that the small striker signed from Leeds United has established himself as the most potent front man at Ibrox in such a short time. ''I am very pleased with him,'' said Advocaat '' and in each game you can see his experience. Besides the fact that he is a good player, he is also good for the team. He fits in.''

The manager made a point of praising Charlie Miller, scorer of the third goal after he came on as a substitute at Rugby Park on Saturday. Charlie took a knock in the stadium last night, but is expected to be OK by kick-off time

After having acknowledged the progress of Barry Ferguson - ''but he has a lot to learn yet''- he said: ''I am also very pleased with Miller and I think you can all see his ability.''

Finally, he emphasised how good a job that Craig Moore has been doing. The Australian has turned in a succession of good performances as a central defender which is the position he wants to occupy. ''I had a discussion with the manager at the start of the season and told him that that was the position I preferred to play in.''

Moore had been a utility player at Ibrox, but he feels that it was a little unfair to judge him on that basis. ''I would rather be judged in the position I feel is my best and this has been an encouraging season for me so far.

''Players are aware of criticism, but Ally McCoist taught me to become thick-skinned as far as that is concerned.''

Moore is aware that once Colin Hendry and Daniel Prodin are ready to play, his place in the team will be in jeopardy. ''It has always been the case anyway at this club that there are four central defenders chasing places but the manager is the type who gives you a chance and then it is in your hands to keep the pressure on him.''

He admits that he did consider the possibility of leaving Rangers as he found himself in and out of the team, but still never lost confidence in his own ability.

As far as tonight is concerned, he says: ''We need to be solid in defence but I don't expect the game to be especially physical.''

The Toumba Stadium will be filled to its UEFA-permitted capacity of 32,000 and no doubt will be as noisy and alarming as its reputation indicates, but Advocaat emphasised that, if Rangers score first, the crowd is liable to give their own side a hard time.

That would be a pleasant scenario for the Ibrox team and it would certainly mean a place in the first round draw on Friday. I expect them to be there.