Manchester United are preparing for their eighth pre-season match (Getty)

Manchester United have had perhaps the most punishing pre-season schedule of any Premier League club – but it seems the toughest test has been saved for last.

Jose Mourinho’s side play in the UEFA Super Cup tomorrow night in Skopje, a match which pits the Europa League winners against the Champions League holders.

While facing Real Madrid was already a tough task in itself, the toughest opponent could be the heat.

Temperatures in the Macedonian capital are currently at extreme levels with Manchester United’s players being greeted with 35C conditions upon their arrival today.

Kids cool off at the Super Cup fan zone (Getty)

When the match kicks off at the Philip II Arena tomorrow evening temperatures are expected to be lingering at around 34C.

So hot is it that UEFA will introduce water breaks midway through each half to help the players cope with the conditions.

The Times report that a delegate from UEFA will measure the temperature 90 minutes before kick-off and if it exceeds 32C then ‘cooling breaks’ will be implemented.

Mourinho has said he wants to win the Super Cup (Getty)

The conditions will be a concern for Mourinho with the match coming at the end of a hectic pre-season and just days before their opening match of the season.

Manchester United travelled to the United States to play five matches, including against Real Madrid, Barcelona and Man City. They then visited Norway to face Valerenga before flying to Dublin to play Sampdoria. Their season kicks off for real on Sunday when they host West Ham at Old Trafford.

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