It's all ifs and buts from here on in, of course, but if Manchester United are to continue to defend successfully their European crown, and if Chelsea are to continue to mount an ambitious challenge for it, then each club must butt a Spanish giant out of the next round of the Champions League.

That was the outcome of the draw for the quarter-finals held in Switzerland yesterday, the stage when the European Cup proper begins. United play Real Madrid, Chelsea play Barcelona.

The welcome separation of the two English challengers in that competition was matched in the draw for the semi-finals of the UEFA Cup. It kept Leeds United and Arsenal apart. Leeds will meet Galatasaray, travelling to Turkey for the first leg, and Arsenal face Lens. The first leg is at Highbury. An English clean sweep remains on the cards therefore. But it is far from a formality.

United's dubious reward for ensuring they won Group B by securing a 0-0 draw in Valencia on Tuesday night is a return to Spain to meet Real, seven times winners of the trophy, with the return in Manchester. The last two winners of the European Cup have not met in the competition since the semi-final in 1968. United won and went on to beat Benfica in the final.

Chelsea's even more dubious punishment for conceding the top spot in Group D to Lazio at Stamford Bridge a day later is the visit of Barcelona to west London in 10 days. It's the Nou Camp a fortnight later. Frank Leboeuf is suspended for the home game.

Should both English clubs progress they will not meet each other in the semi-final, thereby keeping alive Alex Ferguson's hope that the two will come face to face in the final in Paris on May 24th.

To do that, however, Chelsea know they will have to produce what would arguably be their greatest ever European performance: Barcelona, scorers of 17 goals in winning Group A and 36 in their 12 European ties this season, are justified joint favourites with United.

For United the task is only marginally easier. Real Madrid may not be the force they were two seasons ago when they won the European Cup by defeating Juventus in Amsterdam, but they will be formidable opposition despite only qualifying for this stage by winning 1-0 in Rosenborg on Wednesday. Real finished on the same points as Dynamo Kiev but went through courtesy of the teams' 2-2 draw in the Ukraine in November.

Steve McManaman, who Ferguson used have man-marked in United-Liverpool games, is well known to all at Old Trafford. McManaman played against Rosenborg but is not guaranteed a place in the team.

Neither, of course, is Nicolas Anelka, especially as Real have suspended their £23 million superbrat for 45 days. Intriguingly, Real's president Lorenzo Sanz indicated yesterday that a way may be paved for Anelka to return to play against United. Anelka scored at Old Trafford last season.

Anelka's old club Arsenal know their opposition even better having drawn away and lost at home to Lens in last season's Champions League group section.

Thierry Henry, the man who replaced Anelka, was sent off in Bremen on Thursday but yesterday David Dein, the Arsenal vice-chairman, flew to Geneva to appeal against what seemed a harsh dismissal. UEFA appeared to suggest the appeal could work.

David O'Leary, speaking after Leeds' 2-1 defeat in Prague, said that he was glad the side he manages had avoided Arsenal, his former club. "There is the prospect of a clash with them in the final," O'Leary said. "That would be fantastic for English football." It might not be fantastic for Copenhagen, the venue for the final, although a UEFA spokeswoman rejected the possibility of it being switched to Wembley should Leeds and Arsenal go through. "We will not consider moving it," she said.

But it is likely UEFA would indeed transfer it to Wembley. The authorities are acutely aware of the damage an outbreak of hooliganism would do to the image of the game.

The fact that despite there being four clubs from England and three from Spain among the last 12 teams in Europe, none of them were drawn against each other is perhaps a clue as to just how carefully UEFA co-ordinate affairs.

Maybe it is not all ifs and buts.