John Terry celebrates Chelsea’s win over Paris SG.

One of the fiercest rivalries in world football could be re-ignited today when Jose Mourinho learns who his Chelsea team will face in the semi-finals of the Champions League.

Chelsea once again defied the odds to progress in Europe’s top club competition on Tuesday, beating Paris Saint-Germain on away goals thanks to Demba Ba’s late strike at Stamford Bridge.

Twenty-four hours later Pep Guardiola’s Bayern team booked their place in the last four by beating Manchester United 3-1 to prevail 4-2 on aggregate.

Expect few pleasantries to be exchanged between Guardiola and Mourinho if they are pitted against each other when the draw is made in Nyon at noon.

Mourinho and Guardiola were once friends. When Sir Bobby Robson was in charge of Barcelona in the 1990s, Guardiola was his midfield maestro while Mourinho’s role was assistant to the former England boss.

But when Mourinho became Real Madrid coach, they became increasingly bitter enemies.

There is a lot at stake for Mourinho.

He is bidding to become the first man to win the European Cup with three different teams.

A match-up against Real Madrid would also be intriguing for the Portuguese.

Mourinho left the Bernabeu in acrimonious circumstances last summer after winning the league just once in his three-year spell in charge.

Real Madrid have fallen behind surprise leaders Atletico Madrid in the Primera Division and Diego Simeone’s side are making a strong push for European glory too.

Atletico beat Barcelona to qualify for the semi-finals of the European Cup for the first time in 40 years this week and they did it without the injured Chelsea target Diego Costa.

If Chelsea draw Bayern, Atletico and Real would meet for the first time in Europe since 1959.

The first legs of the semi-finals will take place on April 22 or 23, with the return legs taking place a week later.

The Europa League semi-final line-up will also be decided just before the Champions League draw is made.